There's a very simple solution for the anti-cheat problem: make Linux users play only with each other (this also applies to other platform users who refuse to run the anti-cheat).

I'm quite skeptical about their argument though, since on Windows you can also disable secure boot and then run a custom kernel or a custom hypervisor, so it's only valid if their anti-cheat rejects all Windows hypervisors and also checks the integrity of the Windows kernel (in this case it's still of course not secure, but the anti-cheat itself would need to be patched to defeat it).