[The documentation] says how developers need to "test and activate client module updates for Linux regularly in addition to Windows".

But go off king

Yeah, that’s not the whole story

Enabling Linux support does inherently allow more attack vectors that need to be secured that don’t need to be if it’s windows only. Linux works against these kinds of anticheats, as they’re working to get the most information out of the system as possible to prevent 3rd party programs from being run. This is a major design consideration in Linux not present in windows, so there is considerable extra work that has to be done, on top of already being much less effective on Linux than they are on windows.