Because in the UK people believe, media enhances this, they can get stabbed for little to no reason or over a small argument due to mostly due to social tensions but also poverty. In the US it seems you have a high chance of not getting stabbed/shot if you don't agitate. So I think the paranoia about knives does not correlate with the likely hood of getting stabbed but with the unpredictability of it.
I agree that this is the wrong direction to develop into.
From what I could tell a man was stabbed, didn't die, a minor event that happens every day in cities everywhere and always has - and then the locals decided to have a pogrom.
I agree that this is the wrong direction to develop into.