Do you have anything to support that speculation? We have terrible people on all social media platforms. The simplest explanation is that there are genuinely terrible little on mastodon.
They did show their theory. They didn't really show supporting facts. If you claim "it's caused by something different than we see everywhere else" you really need more than "it's true, because money".
On the other hand your explanation is no explanation at all. No possible motivation. Just "people are bad everywhere m'kay".