Just a clash in lifestyles and personal morals, I'd imagine. Personally, though, I believe these supposed "social problems" aren't as pervasive as social media makes it out to be, as I've been in plenty of social groups where vegetarians/vegans and meat-eaters have eaten together and they've gotten along superbly. Most people adopt a "live and let live" outlook but it doesn't appear that way when people are always at each other's throats online.