I agree with others that everything has always been post-fact in a certain sense. The real problem now is that opinions and attitudes are being driven so much

I agree with others that everything has always been post-fact in a certain sense. The real problem now is that opinions and attitudes are being driven so much by ideological group membership. That is, people are explicitly or implicitly making decisions on the basis of "is this the sort of thing that X sort of person would or should do?" rather than "is the sort of thing that is in my best long-term interests?" They're taking for granted what is consistent with their ideological identifications, which often aren't flexible or nuanced enough to deal with the real world. To be clear, I see this as happening on both sides of the political spectrum, although I admit in the US I see it as becoming more extreme with social conservatives.