Eh. It
can happen. I know someone who's paid to moderate [1] a "grassroots" brand subreddit. It's just that "you're not real" is easier to believe than "you genuinely think Donald Trump is the prophesied Jewish messiah." Barring conclusive evidence (which rarely [2]) people gravitate in one direction.
I'd guess it's a mix, with a little straight money, a lot of obsession, and a middling amount of compensated cat herding.
[1] The playbook being basically "discuss reasonable criticism, remove unreasonable criticism" ie "nobody talk too much about that battery fire, but don't make it look suspicious."
[2] "On the Internet, you know everybody who disagrees with you is a dog."