Read the EULA, if you don't want an anticheat that requires those permissions then don't install the game.
Something having kernel access doesn't make it a rootkit, it makes it high-risk for misuse by a threat actor. Only if the software was exploited by a bad actor to acquire root/hardware permissions would this issue actually become something.
That, or if the anticheat wasn't uninstallable and/or dodged scans intended to locate it, etc.