I'm just saying that some devs might view not working on Linux as a feature not a bug

Those devs are exactly the reason why we'd pirate their game with anti-cheats. Not only because the pirated version may work compared to the official one but also, in this case, as a deserved fuck you to the developer.

I'm someone who typically endorses piracy (with the caveat that you should support the people who make the content if you can afford to) yet I will also be the first to straight up buy or not play a game rather than pirating it if it works well on Linux because I think it should be rewarded. And according to Humble Bundle it would seem Linux users pay more than others, so if a specific game is pirated a lot more than acerage on linux then perhaps the problem isn't the Linux community but the game itself and a good dev would see that and fix their game.

Without mentioning that piracy, as stated by Nintendo and other companies, can actually sometimes help a game (for example if said pirate then talks about the game to others who may buy it, or if they then buy it after trying it and liking it).

Either way this is about anti-cheat, not DRM and anti-piracy. And even more-so by automatically excluding every Linux user you're also excluding those that would have paid, that's literally shooting yourself in the foot as pirates wouldn't have paid you regardless (of course with exceptions) but some users would have and you stopped them from doing that with your move.