Actually, if you watch the movie the priest is presented as a man with no compassion whatsoever who just says "you gotta follow the rules, tough luck buddy". It's a very harsh charicature of Catholicism.
Also the priest says to Eastwood's character "You've been coming to Mass every day for 23 years. The only reason someone would do that is because he's done something horrible that he can't forgive himself for". (approximate quote -- I don't have the script).
That's a real solid deep insult to every daily communicant Catholic in the world ... and Eastwood puts it into the mouth of a priest. What an a**hole.
I'd like to say O'Reilly is an idiot for misreading this film but in fact he's a typical example of someone who's a good bit smarter than average and based on that comes to believe he's Einstein.
It is a morality film and Clint doesn't have the guts to stand up for his film's message.