He’s saying that all of the YTAs aren’t justified and that people are making assumptions about him instead of focusing on the facts.

And he's right. Just read your own comments.

I did what he asked.

Oh come off it

I think it was rude to continue a conversation with his MIL knowing she was at lunch with her friends.

That's not what he asked though.

That’s my opinion.

Cool. This is mine. Everyone is allowed their opinion, after all. You judged OP based on a preconception and couldn't let it go. Then doubled down on it when called out, and started negotiating about it. Nothing about this looks like it was in good faith.