I support him. I think what he did was right, and what happened to him justifies what he did to this monster. Hopefully, the Catholic Church will exercise its own demons.
He should've called the police and let them deal with "this monster".
However, from what I've read it doesn't seem that he intended to actually assault the priest in question, merely get him to confess to previous crimes. It sounds like his attack was mostly out of a fear of an attack by the priest, so thus the "yes" vote on this one.
However, I fear a society that is ruled by vigilante rule. You know a pedophile priest? Call the police, call anti-child abuse organizations, call lawyers.....pretty much do everything in legal means besides going over there and just beat the sh*t out of them.
And, I would further add that I am disturbed that anyone would think highly of physically abusing a fellow human being, no matter the reason.