Recently there was a thing where VAC would erroneously flag AMD’s antilag+ feature as cheating, and issue a ban.
AMD then quickly disabled the feature by default but now Valve also patched detection for it and is now, at least according to these patch notes, reversing the bans.
anti-cheat and drm aren’t the same thing
complain all you want about anti-cheat, i would rather play a game that has it than one that does not