Don't let him up, move on to his next offensive comment. No mitigation, no apologies. Heap scorn and derision on the asshole and DON'T stop.

The only (best) way to haandle that son-of-a-bitch is to hurt him and keep him hurting. Pay no attention to his protestations - the man is a coward and if one Stay with it he will corner himself.
Another trait. He cannot apologize, at least not sincerely. So it will be relatively easy to back him into a corner. Don't let him out, don't argue it, just move on to the next hole he's dug for himself, or go back to the last one. Doesn't matter.
Remember, the guy is a coward who cannot stand up to someone who picks him apart withoout mercy, without trying to be "fair", without "I sort of see your point
bullshit.