If you accidentally ban linux users in three[1] different[2] banwaves[3], then linux was only halfway supported in the first place, even if they overturned (almost) all of those bans.

I think the real reason they did it was EA's financial situation. Since money is tight, the amount of resources they were willing to put into real linux anti-cheat probably dropped to "none at all," and now we're here. Otherwise other cheater-prone games like Counter Strike, Overwatch, Halo, The Finals, DayZ, Hunt Showdown, etc would have probably dropped/blocked linux by now too.