The only thing you can control is your reaction to others' words and behaviours, you can't change these for them.

Staying calm in the face of confrontation can help defuse aggression. If it doesn't, then they're looking for a fight. Remember, just because a person yells the loudest, it doesn't make them right or wrong. The calmer you remain, the sillier they look (even whilst they feel smug and superior). Pity them, if you can, for feeling so insecure they need to browbeat others. And if someone feels insecure and defensive, you can't change that - that's their own self-esteem issues. Some people need to feel persecuted, unfortunatley.

You can suggest that you agree to disagree on things. Some things that can be useful include:

"That's an interesting perspective, tell me more..." followed by lots of eye contact, nodding and "ah huh", "mmm" etc. They get to be listened and you get to think "WTF!" in your head. (If you feel like being a cow, wait til the end, then look all wide-eyed and state "What a fascinating way to look at the world! That works for you does it?" but then you'll really start an argument)
"That's an interesting way of looking at things."
"That's one way of looking at things, I agree. Not the way I see things, but isn't that what makes wthe world such an amazing place...do you mind passing the potato salad?"
"Hmmm. Well, that's an interesting theory. I think we'll have to agree to disagree there. Where did you get that fascinating [insert object here]?"
"I can see you feel passionately about X. Good for you"
"Wasn't it Voltaire who said, "I disapprove of what you say, but I will defend to the death your right to say it?" btw - it wasn't Voltaire, but is comonly attributed to him.

Otherwise, if none of that works, humming to yourself and imaging them all naked/in their jammies, may help you stay sane.

GL