This isnt as much about the misuse of the term design as you make it seem. The author is right that free software is generally not as well designed as its non-free counterparts. Most of the time bad design manifests itself as too much complexity, strangely organized settings menus, way too many settings to begin with. You seem to have this "screw the average user" mentality which I'm guessing comes from the fact that average folks don't tend to use free software (mostly referring to Linux the OS and Linux software but it does apply to other platforms some of the time too).
If you're making software for the power user set then the status quo is probably just fine but if the free/open source community really is committed to winning the hearts and minds of users of the standard platforms (Windows and Mac obviously) and really do want to get a bigger piece of the market share pie then developers will have to dumb things down a bit and simplify.
The attitude you seem to have towards users, calling them dumb people and meat stacks, is exactly the thing keeping those dumb meat stacks from using free software. Programmers also seem to hold a sort of bigot attitude toward designers which your comment also exemplifies. Functionality, elegance, resuability, and everything you mentioned are great and necessary but there's no reason it can't be prettied up a bit and simplified.
The bottom line is that if you're developing software for people just like you then you can ignore the dumb meat stacks and the pesky designers and still be successful but don't ever expect average users to educate themselves in order to use your software. They don't care about the limitations of technology and how everything works together nor do they care to learn. They just want to press button X and have action Y happen with the least possible friction in between. If button X doesn't get action Y to occur as fast or easily as they want then they're uninstalling your app. That is, unless uninstalling involves more than a click or two otherwise it'll just collect dust and consume disk space. Until you design and develop with dumb meat stacks in mind only programmers and power users will use your software.
Now im not saying this will be easy nor am I saying free software developer have to start doing this. After all, they work for free I'm their spare time and create amazing amazing products and alternatives to non-free software. What I am saying though is that this is the reality of dealing with users. It's not ideal and they certainly act like an entitled lot but it won't change especially now with the proliferation of prettified and dumbed down apps everywhere you turn.
They just want to press button X and have action Y happen with the least possible friction in between.
I don't think that this is just an attitude for less technical users, I have the same attitude myself whether I am configuring an HTTP server or playing a video I want a low friction way to do this. I don't think that power users exactly seek out the hardest interfaces.
The problem is though that the highest friction way to do something is to not be able to do it at all and have to work around that. I think this is why there is much resistance to things like Unity on Ubuntu.
It's also worth bearing in mind that consistency is also important, so doing something like releasing an "easier" Window Manager that is a huge departure from what was there before will not necessarily be welcomed by users as much as you think.
Having said that , I don't think that usability is the #1 thing holding back FOSS desktop adoption. The biggest things are MS inertia and also compatibility, for example without Silverlight4 + DRM you can't use things like netflix which is going to really hurt adoption (although I'm not sure what could be easily done about this case).
I also have that mentality of wanting no friction but I guess I was really saying that users like me and you can deal with it in most cases while the average people won't tolerate it.
I was mostly talking about keeping this in mind when developing new software. It definitely will be hard to make big departures from what's already in existence. It's not impossible though. You can always give users the option to add X toolbar to a window and choose which buttons appear by default and such.
Of course, these solutions don't lend themselves to all software and that's okay. What's really important is just to keep these ideas in mind and not write off design as just unnecessary ornamentation in the future. Obviously we have to be thoughtful about where these ideas would work best. The easiest way to do it is know your target users and design for the least common denominator among them. Your software can launch with a design meant for the least common denominator by default with options which can be displayed and remembered later for more advanced users. I can't repeat this enough though: this can only work on a case by case basis and by knowing your users. Remember too that incremental departures are swallowed much easier.
Design may not be the number one thing holding back FOSS adoption but it's high on the list I think. When the FOSS community can offer equal or better alternatives to what's out there, market share will skyrocket. I think Linux is pretty much there already. It has a few blemishes but the big thing is probably that normal folks are just scared to try it, won't go through the trouble of installing another OS over the one that came with their PC and the appalling lack of computers that come with Linux pre installed.
I'm not sure if I have a higher tolerance for bad usability than other people, I find I am often more vocal complaining about it. Besides if you watch a highly non technical user use a computer they will often do things in incredibly inefficient ways and don't seem to worry about it too much.
I think the key though is making it as difficult as possible to get stuck when trying to do a particular task. This is where consistency is hugely important, if most of your apps work approximately the same way (such as with Apple) and have predictable behavior this is hugely helpful to users.
There is also a lot of context to bear in mind when thinking about how easy something is to use and I think this is where it does a disservice to lump "non technical" users together.
For example , I grew up during the days of DOS so switching to a UNIX/BASH command line when I got older felt very natural to me. However I wouldn't want to put myself up against the average 15 year old of today when learning how to use the latest social network.
Regards FOSS applications, one thing to bear in mind is FOSS is by nature easier to port than proprietary software. Therefor most of the good Linux desktop apps are also available on Windows which in many ways actually damages Linux adoption.
For example I know plenty of Windows/Mac users who are using Firefox , VLC and Pidgin. There would not be a particularly big tangible benefit for them moving to Linux (apart from saving MS license money they already spent in the price of their PC).
On the other hand it makes it easier in the sense that most of their familiar apps are already available.
If you're making software for the power user set then the status quo is probably just fine but if the free/open source community really is committed to winning the hearts and minds of users of the standard platforms (Windows and Mac obviously) and really do want to get a bigger piece of the market share pie then developers will have to dumb things down a bit and simplify.
The attitude you seem to have towards users, calling them dumb people and meat stacks, is exactly the thing keeping those dumb meat stacks from using free software. Programmers also seem to hold a sort of bigot attitude toward designers which your comment also exemplifies. Functionality, elegance, resuability, and everything you mentioned are great and necessary but there's no reason it can't be prettied up a bit and simplified.
The bottom line is that if you're developing software for people just like you then you can ignore the dumb meat stacks and the pesky designers and still be successful but don't ever expect average users to educate themselves in order to use your software. They don't care about the limitations of technology and how everything works together nor do they care to learn. They just want to press button X and have action Y happen with the least possible friction in between. If button X doesn't get action Y to occur as fast or easily as they want then they're uninstalling your app. That is, unless uninstalling involves more than a click or two otherwise it'll just collect dust and consume disk space. Until you design and develop with dumb meat stacks in mind only programmers and power users will use your software.
Now im not saying this will be easy nor am I saying free software developer have to start doing this. After all, they work for free I'm their spare time and create amazing amazing products and alternatives to non-free software. What I am saying though is that this is the reality of dealing with users. It's not ideal and they certainly act like an entitled lot but it won't change especially now with the proliferation of prettified and dumbed down apps everywhere you turn.