But then, what makes some people on the left able to step out of the package deal, and say, hang on, something's not right here ?
I think you are right to point to a strong awareness of material reality, but that's tricky isn't it, these skeptics think they have that, it's why they are so strongly attached to empiricism, and an extreme kind of empiricism that's been largely rejected among philosophers as having insurmountable problems. That is maybe notable, as is their real lack of grounding in the epistemology of science itself. They think they know a lot more than they do.
Thinking about this, something I have realised is that I've always been inclined to question the dominant narrative, but also disinclined to dismiss a narrative because it is dominant, or out of fashion. That seems to be down to personality, but now, in middle age, I have a lot of experience in being out of step in one way or another with almost every group, and with people on all sides of the political spectrum thinking I'm wrongheaded in some way. That's helped me personally with all this identity politics bs, because it really has bothered me a lot being considered an outright bigot.
Something which I think may be related that I've noticed in recent years is that there are quite a few people who never really question that they are good. Maybe this has always been the case but I noticed in particularly after having a conversation with an individual where I suggested that introspection to avoid embracing evil or self will was important for everyone, and she was very angry, and told me that neither she nor her children were evil. I was a little surprised and realised I had perhaps always assumed that I and others have a capacity for evil, though of course most people don't embrace that all out in their lives.
I started to pay attention after that and I've come to think that many people assume that their intentions are always good, and that if they do something not good it is always simply error about facts or something like that. And they also seem to have a similarly black and white view of those they think are bad, that they really intend to be bad, that they know that is what they are doing, etc. That good and evil or whatever words people want to use are often mixed up, difficult to differentiate, that our own motives can be self-serving and we can be blind to this - these are not common ideas for many people.
What I wonder now is if this has always been the case? Maybe it is just that the bulk of people tend to take that sort of simple view, they don't really question what the dominant social perspective is. I think this ability could probably be improved somewhat through education, but I think that we have moved instead to a form of education that strengthens those ideas, and perhaps providing that kind of education on a widespread basis is very difficult to maintain.
Anyway, I think it's the million dollar question, why can't some people step out of the box.