I don't know enough about D&D paladins to argue intelligently. I suspect that, in actual medieval times, anyone choosing to believe a sword over the established church hierarchy would be executed as a heretic.
Yeah, look, D&D, even at it's most crustiest of crusty, was never really modeling the "actual medieval times". So that's kind of a meaningless statement. In "actual medieval times", you didn't have paladin
as D&D understands the concept... The idea of a divine conduit to a god, going around and healing with a touch and stuff? He'd be considered a saint or a prophet, a legendary figure. In D&D, he's not that special.
But in any event, even if you assume that people wouldn't believe the Paladin, for literally being able to sense evil, or know when he Fell, or when his magic items stopped working? Again, D&D as written has objective morality. That's, again, just saying that the church is corrupt/evil.
So you’re relying on the definition of good given in D&D. Gary Gygax wrote the Player’s Handbook that gave a definition of Lawful Good, but somehow he doesn’t seem to find a conflict in how he thinks of Lawful Good on Dragonsfoot, and what he wrote in the Player’s Handbook?
If you’re relying on the definition of good as given in D&D, and Gary defines and describes Lawful Good in a way that you disagree with I’m not sure how you can rely on D&D as an authority to refute its author.
If you’re referring to a different edition of D&D than what Gary wrote we may have a case of comparing apples to oranges.
And Ray Bradbury would later go on to say that the true message of Fahrenheit 451 was about the evils of television, while J.K. Rowling says that wizards used to go around shitting their robes and just magicking the feces away. As much as I'm one of the Tolkien scholars who will drag out things the man said in letters and such, I can recognize that sometimes it's best we not pay too much attention to stuff authors wrote after the fact.
I'll accept that Gary feels a certain way. I disagree with Gary. I don't think the work Gary published supports the views he espoused 30+ years later on an internet forum. If pressed, I'll go so far as to say as much as I respect Gary, I think his interpretation is stupid.