Well, they think their ideas are perfect and unquestionable. I don't think it doesn't occur to them that other people would disagree, just that those people are either a.) in the minority and/or b.) morally beneath them.
I suspect they've just built a strawman in their heads that anyone who would criticize is probably a weak person that wouldn't stick up for themselves or would be brave enough to laugh. There might even be a bit of "if someone criticizes, I have plenty of people to drown it out with praise, and to stick up for me. They'll be overwhelmed by the mob that would attack them on my behalf because I'm the main character!"
It's really the "punch a Nazi" argument. They never think the Nazi is going to punch back. They never think the person they accuse might not be a Nazi. And they never think that the person they're accusing of being a Nazi has a way more persuasive argument than they do.
You're 100% right and, just to add to this, it's that their brain plays a trick on them that leads them to believe anyone morally beneath them doesn't exist. I mean, they do exist in the sense that they disagree with them, but they don't exist in any tangible way when it comes time to vote.
You see this a lot with the immigration issue in the US. A lot of people, a growing amount, don't want unchecked immigration from poor countries, don't want their town to become 60% Mexican in the next decade. A lot of lefties will look at that view and say, "that's racist," and sure, not wanting certain people to be the racial majority is racist. But they take comfort in labeling people negatively. "That's racist," in their mind, is shorthand for, "that's why your vote won't be counted." Then they're horrified when someone like Trump is elected, and point to foreign interference as the only possible explanation.
The fact is, that basket of deplorables, they all vote.
You see this as well in elections where they say "X candidate or ballot measure is broadly supported by non college educated voters." Lefties will breathe a sigh of relief, because to them that means that there aren't enough people to vote for it at all. Uneducated, not motivated by the right reasoning, misguided, all of these things give a Leftist a sense that the opposition against them doesn't exist.
One last example, you may notice how you can't speak negatively about the political question on trannies unless you make it clear that you're coming from a place of concern, that people transitioning just to kill themselves is tragic. Rarely do you see anyone like Null who is like, "Yes I do hate them, AND here is why you shouldn't support them either." I mean, you can say that, but no one on the left will be able to think of you as a real voter with a real ballot. Which is weird.
