Pastors are shepherds of souls. They are charged with keeping the wolves away from their flock. So why would they let someone be abused, by another parishioner or even by a group of parishioners?
One explanation is that they don't know what's happening. They may be blissfully unaware one of their sheep is being mistreated.
Or they may know, but believe they're unable to help. Pastors are only human and they're subject to the same weaknesses and temptations as the rest of us. Deep down, they may be afraid of the bully and his or her cohorts. Although I don't condone this type of hands-off approach, it's easy to see how someone chooses this route. Catholic clergy are under a great deal of pressure. They must run a small business, often with little help and a limited budget. They're also painfully aware that it's easy for anyone to level a charge of misconduct, even if there's no basis. So they take the path of least resistance, at least for the short term.
It's possible the pastor knows what's going on, but doesn't really believe that someone is being bullied. He (being human) may have heard unsavory stories about the target, from several different sources. He doesn't think multiple parties would fabricate the same tale. So he goes with what seems the most plausible. Abusers are very good at recruiting others to "help" their cause.
People with disordered personalities can appear holier than thou. It's possible the pastor thinks highly of them. Unless he's personally confronted someone with narcissism, he probably can't even fathom how one (or more) of his favorite parishioners could be so devious.
Sometimes, the pastor has a character flaw, and he abuses the sheep he's supposed to protect. If that's the case, pray for him.
Flickr photo by gwp57