Doesn't the PIS thing apply to Joker as well a lot of the times he steps outside of Gotham to mess with any of DC godlike super-people?
I mean, he too is a very dangerous fellow. But ultimately his physical abilities are supposed to be just that of a normal dude, and he some times pulls off feats that just seems like the universe put itself on Easy mode so that he can feel like a real big bad when he's not playing with people dressed up as bats and birds.