But the internet does have a lot to answer for - I remember years ago reading an article that pointed out that in olden times, the village idiot was isolated and therefore usually no harm was done. But now they go on Twitter or Tumblr and say stupid things, and find people who agree with them - and boom! An explosion of idiocy.

THIS. And not only do they find like-minded people to hang with, they isolate themselves by tailoring their friends' list (or whatever they call it on various sites), and it gives them the impression they are a lot more prevalent and powerful than they really are, and that proceeds to confirm their crazy and spurs them on. :/