They get paid in the satisfaction of exerting control over others, enforcing their bias in a community, and generally feeling powerful. That's the kind of person who tends to self-select to delete posts and ban people all day for free. Moderation gets so bad on reddit (visible from subreddits like watchredditdie and nolockedthreads) that many communities would be better off self-policed solely by up/down votes, all tradeoffs like spam and bad posts considered against the tyranny.