I do wonder whether some of the hand-wringers hereabouts aren't reading too much into too little (and/or what they've heard/read, as opposed to actually experienced.)
I'm doubtless guilty of the same thing, tho' in the other direction, on account of I'm fortunate enough to live in a nice family-friendly bit of North London and work in prosperous Covent Garden, but certainly my impression is that people around me are overwhelmingly pleasant and polite - particularly the young, who get so much bad press these days. And compared with my youth, back in 'the good old days', real nasties like racism and homophobia are a shadow of what they were. When I was a kid, my peers used 'wog' and 'nigger' as a matter of course, and even quite 'nice' people got their paper at 'the paki shop'. All gone.
I'm obviously in a minority here, but in my view, speaking as one knocking on his half-century, things have got better, not worse, in my lifetime - in terms of the ways people interact with strangers. There are of course exceptions. There will always be scumbags. But I find people, around me at least, mostly decent and civilised.