I can understand the way you felt in that situation, however you could have asked to be seated somewhere else.
As a military person I know what torture is and what isn't. There is a difference between humiliation and real torture.
I have been tied up and burned with a hot knife, had objects inserted into me, beaten and bruised and spit on and left lying in urine after being urinated on.

You have suffered things too and for that I am sorry. The hardest thing to do is to listen to someone else's opinion that you disagree with and not become violent. I truely believe that actions speak louder than words and that in the USA, at least for now, we value freedom of speech and detest censorship. Opinions vary from place to place and for person to person but, unless that person is making direct threats agains someone, they have the right to freely express theirs, we don't have the right to not be offended. Taking yourself out of that situation before it escaleted would have been better, but at least you didn't get yourself in any altercation which could have gone badly.

I know if it had been me in that room I would have left, so I agree with your decision to leave.

Have a great day,