Better yet,
“I’m sorry you took offense at being called a subhuman mongrel”.
Personally, I don’t think he should have used “subhuman” in his rant, but calling him out as an authoritarian tyrant bent on communism would have been more appropriate.
There are many words that Mr. Nugent might have appropriately used, but I won’t list them here, as I don’t want to offend the fastidious.