I suspect people are thinking about a statement from a game developer who said that enabling EAC support for a Proton is just a checkbox. But I'm fairly sure that only exists because the EAC developers have made a version specifically for Proton. Wardogs uses EAC so it's all good, but it's not generally true for all anti-cheats.

Specifically, it's that linux doesn't allow someone a gilded-path method to ursurp control of your computer like windows does. The 'switch' in this case is turning off where it tries to, effectively, hack your computer to give control of it to the company installing the anti-cheat. We have a name for that type of program- it's called a rootkit, and it's a major security vulnerability that game companies are trying to rebrand so they can save money on client-side anti-cheat instead of spending money on server-side anti-cheat.

For the record, it's a losing battle- client side anticheat will NEVER be reliable- it literally can't, because at the end of the day you still physically have your computer.

It does. The switch in some anticheats is to just not require that on linux. Also not all anticheats are kernel-level in the first place.