I’ve felt it too. I can’t fight the feeling that it happens to attract a certain kind of mentally ill person. Specifically, the preponderance of anxious, neurotic persons, often with a persecution complex and a militant ideology, is enormous. The result is a climate of unbridled vitriol and outright hate for whatever group they hold responsible for their woes.
It increasingly feels like Reddit is a breeding ground for various types of extremism (usually left-leaning, with some notable exceptions).