If I played any Rockstar games, I’d be unhappy with their new anti-cheat too, since it needlessly blocks linux, but this isn’t the way this should be protested. If anything, this probably validates their decision.
The way this should be protested is to just stop playing. Stop giving them money. Stop boosting their month active user numbers that they can flaunt to investors. Hit them financially, since it’s the only hit they really care about. There’s a sea of other high-quality games you can play instead.
If you accidentally ban linux users in three[1] different[2] banwaves[3], then linux was only halfway supported in the first place, even if they overturned (almost) all of those bans.
I think the real reason they did it was EA’s financial situation. Since money is tight, the amount of resources they were willing to put into real linux anti-cheat probably dropped to “none at all,” and now we’re here. Otherwise other cheater-prone games like Counter Strike, Overwatch, Halo, The Finals, DayZ, Hunt Showdown, etc would have probably dropped/blocked linux by now too.