I think that this is a great point. It's far too common for people to think, "John is completely opposed to my beliefs. He's definitely not stupid, as I know from other conversations with him that he's thoughtful and sincere. Well, that leaves one option - he's a bad person."

Often, this results from taking the bad intentions of certain people who believe such things and applying them to the whole.

"You're for / against X program. There are people who are for / against X program because they have an immoral ulterior motive. Therefore, you have that ulterior motive too!"

This naturally leads to fingerpointing and yelling.