It's a way to give Christians the bird. That's all.
So far as I am concerned, the crucifixion cannot happen quickly enough.
The Romans thought it an excellent way to execute criminals, and in fact, MANY criminals were hung on a crucifix, to die in agony in public. The gallows and the guillotine are only newer and much quicker ways of public execution.
But like Robespierre, wishing these ends upon another sometimes comes around to claim its greatest proponent.