In her heart, I'm sure Sara Brady wants good men to be protected from whackjobs with handguns. MADD wants their families to be protected from booze guzzling drivers. There's nothing wrong with this. Everyone wants things, it's what they're willing to do to get them that gets to be problematic.
If I saw my little dog had been hurt by a perverted reader of pornography, or my little nephews hurt, or my daughter hurt by a porno worshiping person, I think I'd be willing to do something to fight that perversion whether it became a problem for me or not.
When the fruits of perversion hits close to home, the tolerance factor ends with most people.