I think that this sort of incredible emotional fragility arises from something else that precedes a person's Left-wing political orientation.
Like "an overriding inclination toward social comfort" or something.
Our grandparents might've just called this shared root cause "weakness of character."
And then that inclination causes people to hate disagreement and react poorly to new ideas, but it also causes them to prefer the short-term-thinking "wouldn't it just be nice if..." side of politics because all of the "don't worry, you already have all of the Good Person answers, you're on the right side of history" shit and the "unintended consequences, what are those?" shit placates their emotions.
I remember Aydin Paladin having a good video about how socially-negative outcomes (losing a competition or an argument, being ostracized, being disagreed with, etc.) actually causes people physical pain, and I'm sure that the psychology and physiology behind that would be useful for my theory, but I can't find it right now.
I could find
this study showing how small the range of "acceptable opinions" is on the Left. So people on the Left are going to have way more things that they disagree with / can't even consider / get mad at you for even bringing up.
