Piazza lost votes because one time someone saw pimples on his back. When it comes to having a gripe over voters being stupid, get in line Curt.
I'm guessing people saying that he is gay probably also cost him some votes. The Hall of Fame voters are a bunch of old white guys. Some voters haven't covered the game full-time in years.
Character/Integrity leaves a lot of wiggle room for men who aren't even required to provide an explanation for their votes. They don't have to disclose either. It wouldn't surprise me if voters didn't vote someone in because they didn't like someone for racist reasons. I'm sure that also extends to religious and political reasons too. Schilling made stupid comments to Twitter, he's been publicly shamed for stealing public money in Rhode Island, and was a noted jerk to all those who know baseball.
I think Schilling loses votes for being a jerk more than he does for being Christian or Republican.
He was a great pitcher though. Baseball writers also get a kick out of holding guys out. They're punishing Bonds and Clemens right now. Bagwell is getting punished too. Piazza had pimples on his back according to some middle-aged baseball scribe, so he's juicing.
Schilling is a jerk, but he's not too far from the truth. Baseball writers will use any petty reasoning to hold someone out of the Hall of Fame. It makes them feel powerful.