From the same place that real-life competitions tend to have rules about cheating that are enforced.
Why do people think that they get a free pass because they can't see the opponent face to face?
If you want to play with friends, plenty of multiplayer games offer that without anticheat (Arma lets you even uninstall the anti-cheat and play on anti-cheat disabled servers).
Does my local basketball competition requiring all competitors to submit negative doping tests before competing? Do they get to monitor me for 24 hours before the game?
Because that's the level of seriousness of most gaming and the proportionality of using a rootkit to prevent cheating. Sure, the Olympic athletes (or I guess in this analogy, eSports pros competing online) get the full "we're going to make very sure you're not cheating approach" but "my local basketball league" or "unranked ladder" doesn't justify these measures being routine
Why? Do I get to pick the people on the opposing team in the local basketball competition? I didn't specify a local club for a reason. Just because it's some competition organisers rather than a matchmaking algorithm doesn't change my perspective.
> Why do people think that they get a free pass because they can't see the opponent face to face?
We don't think that. We think anti-cheating rules aren't important enough to justify shipping literal malware to people's computers and taking over their machines.
It's not literal malware though, unless you have proof that it does something malicious like encrypt a users directory or exfiltrate sensitive data and that every single anti-cheat does that.
Why do people think that they get a free pass because they can't see the opponent face to face?
If you want to play with friends, plenty of multiplayer games offer that without anticheat (Arma lets you even uninstall the anti-cheat and play on anti-cheat disabled servers).