Comment by hilux

Because computer-aided cheating is trivial to do and known to be widespread.

It's apparent that chess.com has tuned the detection threshold to near certainty, which lets many cheaters through, at least for a long time.

What often gets lost in criticism of the corporate entity is that undetected cheating (i.e. false negative by the anti-cheating software), which is very common, also has a cost, and victims.