I always thought it had to do with the internet.
It has gotten pretty rough. I read a lot of sports
articles eg golf, tennis, football etc and now we will get
the olympics.
They are encouraging for people to react and there is so much spam that I report there.
Because of the internet we are also more exposed to all kind of people who we probably would not have met in our
daily life.
Andreas Moritz used to write about something similar you mention, but I never paid
much attention to it, so I can't remember what reason he gave.