There's a difference though.

If the game doesn't work for (some or all) Linux users, that's not a big problem from Epic's POV. They'll lose a couple users that wouldn't have been able to play the game without Linux support anyway.

But if the Anticheat faills on Linux, that is a completely different story. Then cheaters would all dual boot over to Linux to cheat all they want. That's now a problem for the whole game's user base and consequently for the publisher as well.

Something as low-level as an Anticheat would have to be rewritten almost from scratch to work on Linux and this one really needs to be tested with every possible permutation of installed relevant software. Because if one combination is found where it doesn't work, you can be sure that the day after every cheater will be running this config.

(Just to check, do you have a background in game development and/or low-level Windows/Linux programming? I got all of that and I can tell you, nothing that looks easy from the outside is actually easy. I think you are vastly underestimating how much work goes into something until it "just works as expected")