Never surrender to such a moron. You leave the class and he won, not in your eyes and you could care less about his eyes but in the eyes of those whose brains are full of mush and know no better.
You left, he stayed, he must be right. That is how your classmates who know no better will see it.
I went to a fairly conservative school. Engineers, pilots and a very large AF ROTC program (just behind that fancy school in CO). Still we had our share of fruit loops in the humanities department. One sociology and history prof was a WWII vet from the Pacific and had the more "practical" mindset. His history final had a question which was "Your professor feels the bombings of Nagasaki and Hiroshima were justified, give two reasons he gave in class."
Then there was the PETA fanatic who also considered the Swiss the ultimate pinnacle of society because "they are non-violent and always neutral." Still I never missed one of his philosophy classes and:
made a point of wearing an NRA shirt,
explained to him why the Swiss Guard for the Vatican were mercenaries considered to bloodthirsty by the rest of the world to use and were therefore forbidden working for anyone but the Vatican and as guards,
why it is easy to be neutral at the top of a mountain,
the mandatory military service in Switzerland,
the presence of a fully automatic weapon in the home of every Swiss male between 18 and 42,
that the financial contribution to conservation in this nation by hunters far outweighs that of those who supposedly are trying to save said animals.
that only in African nations which have established controlled harvesting of game do such animals thrive thanks to the revenue they generate and the benefit they become to the population.
on and on.
I NEVER walked out. Winning in his eyes or yours is not important. Winning in the eyes of the undecided or those who are open to reason IS important.
As far as his calling you a terrorist, I would tell him that you are going to report that statement to the administration, the NRA and the media, and any alumni groups you can contact. A full apology from him in front of the class is warranted. what is more:
The professor said that I would kill and die for my beliefs makes me the same as those we are fighting against in Iraq and Afghanistan.
and what exactly are our troops killing and dying for in Iraq and Afghanistan if not our BELIEFS?