Well, that's not strictly true.
If one is devoted to an ideology-based political movement, one still has to figure out who the other members are, what the accepted membership signals are, what topics are acceptable to bring up within the group ("Oh, we don't talk about Obama being a Kenyan anymore? But it's OK to say Syrian refugees are terrorists?") and so forth.
Now, as it turns out, human beings are very good at this sort of cognition. For most of our evolutionary history, our survival and reproduction was FAR more dependent upon our ability to maintain good standing within our social group (i.e. our hunter-gatherer tribe) than on our ability to reason correctly about empirical reality. So our brains are much more adapted to social group dynamics than abstract Type 2 cognition.
It's not fair to say ideology-based group identity means not having to think. It is somewhat fair to say it means exerting much less effort to think, because that mode of thinking is something which comes easily to us.