Without hard data it’s difficult to tell to what extent this is accurate, but there seems to be a substantial portion of Linux gamers (including Steam Deck users) who are pissed off that due to the anti-cheat they can’t play the game on their platform of choice anymore. Some of them may have joined the DDoS campaign, so there is a genuine venn diagram.
I don’t play multiplayer games, so I can’t tell what kind of people the cheaters are. But speaking for myself, I did change my ratings from 5 stars to 1 and was very vocal whenever an upgrade to a game I purchased broke that game on my system, and there wasn’t a way to roll back. Given that those were single player games, DDoS wouldn’t hurt them, so I just kept spamming their support e-mails.