Some of it is definitely bots, but don't discount the human factor either. Russia had an entire branch of the military dedicated to trolling the Internet at least as far back as 2015. Something tells me that hasn't gotten smaller since then. No doubt they work in tandem with bots as well, constantly editing their output, maybe even making posts from the same accounts.
The fediverse may be small compared to the behemoths, but I don't think we're so small as to be ignored.
Valve has made attempts to take down projects that follow those rules. TF2Classic is the example that comes to my mind since it's the main one I've played, but I know there are several others. In TF2C's case, they tried contacting Valve to find out why they'd been hit with a C&D, never heard back, and eventually quietly resumed development.
Some kind of miscommunication between legal and the devs? Maybe internal drama? Maybe they didn't really pay attention and still aren't aware TF2C is back up? Who knows. Still happened tho.