The "down side" is that their side gives up nothing in this "compromise". All they are doing is changing the subject.
Exactly. "Why not just give up and accept the fact that we've won?" This is a despiration tactic, because the pro-death crowd realizes that their side won by resorting to the non-democratic judiciary, and that after thirty years of abortion by royal fiat, they still haven't convinced enough people of the correctness of their position.