He's a game developer and Twitch streamer (game dev and playing) who's become very popular in the last few years.
The latest pile-on against him is due to him having some reservations about the wording and intent of the petition/movement and, because we're currently in a era where False Dichotomy is king: anything other than 100% unquestioning support is treated as 100% unequivocal opposition, and vice versa. 😒
My understanding is that he thinks it's a good idea in principle (as do I), but games are no longer simply compiled with only the occasional update or patch, but multi-server online complex systems with a lot of moving parts. Of you're going to legislate immortality on games, then you're going to need to make your argument for it clear and robust, who has responsibility for what, how deprecating technology is handled, and so on.