They do this with Early Access and people still lose their shit about empty content and unfinished graphics in a game they paid $10 for.

Adding kernel malware after the fact should entitle every single owner who requests one to a full refund no matter how long has passed.

Oh it was initially classed as insanely intrusive malware when kernel level AC was introduced about a decade ago, by anyone with a modicum of actual technical knowledge about computers.

Unfortunately, a whole lot of corpo shills ran propaganda explaining how actually its fine, don't worry, its actually the best way to stop cheaters!

Then the vast, vast majority of idiot gamers believed that, or threw their hands up and went oh well its the new norm, trying to fight it is futile and actually if you are against this that means you are some kind of paranoid privacy freak who hates other people having fun.

Do you remember when Sony released cds that when inserted into Windows computer auto ran an installer that installed a rootkit that made it impossible for Windows to see any processes or files that started with a certain sequence of characters instantly turning any malware that named its files or processes similarly powerful rootkit. Oh and it installed a cd driver that made it impossible to copy their music.

Suggested removal was a full reinstall of windows.

Making it super simple, it runs with full access on your machine, always. It can fuck anything up, and see everything. It can get your browser history, banking details or private messages you enter, activate your webcam or mic without you knowing, or brick your computer even.

And you can't even check what it's really doing on your computer because it's a crime under US law.

Finally, it can get hacked and other people than the creator can do all these to your computer as well,as it already happened once.

Easy, a bug in battle eye forced me to reinstall windows, this kernel access has to go.

Because there are kernel-level cheats

What you proposed can very easily be bypassed without even needing kernel access by just editing the executable code that checks hashes to always return true

Modern cheats for multiplayer games don't modify local files (or attribute values in memory), since the server validates everything anyway. They're about giving you information that's available but not shown in the game (like see-through walls, or exact skill ranges), or manipulate input (dodge enemy damage, easy combos). Those cheat can run in kernel mode (or at least evade detection from user mode), so the anti-cheat needs kernel mode to be more effective.