Fivepastels. I think you penetrated his bubble of cognitive dissonance and he didn't like it
Exactly this. People don't like being made to think about what they say they believe, because when its pointed out its dumb as fuck, they take it personally, that they are also dumb. The person pointing out the idea is dumb as fuck often is on the receiving end of that embarrassment and they are blamed on a personal level for somehow being responsible for someone's own lack of ability to think. They are labelled are superior or otherwise nasty for stating the bleeding obvious even if its in a neutral and totally reasonable and non-confrontational manner.
All because people don't like feeling stupid.