Entirely appropriate as you get up and leave. Seriously. There is no other appropriate reaction unless you're terrified of retribution because it's the USSR or one of the wannabes. Price of freedom, etc. etc.

I'd be throwing in the word "Traitor" if it were me, but only on the basis that it is absolutely true.

After being accused of sex with animals, it's still probably unwise to discuss fucking the high horse someone rode in on.