Forum admins think they can do whatever they want

So a few days ago I ended up in a private argument with an admin on a forum that I’m on. We resolved the argument, I thought, peacefully and no harm was done. Then yesterday he picks a fight with me about it in a public part of the forum and punishes me for being “disrespectful” after I said “please don’t bring this up again, especially in public”.

I’m inclined to tell him “you can’t punish me when you unambiguously started it this time”, but I’ve tried that before with admins and it always makes things worse. Somehow they think they’re always right, no matter what they do and even when it’s clearly wrong.