Sure, but from the end user perspective, it doesn't matter whose fault it is - the result is you can't play a game you otherwise just can in Windows. We know it's their fault.
If you never play any games with anticheat that's fine, but all it takes is one game, and then later another, and then later another, to make Linux a dealbreaker for many gamers. These are not unpopular games.
It can be the whole difference between someone sticking with Windows but itching to make the switch, and someone actually making the switch.
What good is 90% of games working if you have 3 games that you really want to play that don't work?