I've lived in cities on both sides of the political coin and can comfortably say that this is consistent for both liberal-dominant and conservative-dominant cities. I think part of the problem is that a lot of the issues you mention are seen as moral rather than ideological because peoples' values become so deeply rooted once they've spent enough time in like-minded communities (and perhaps some of the issues were really a question of morality to begin with). Beyond that, there's a heightened degree of generalization of "the other" when you're in a homogeneous community - if you support anything that aligns with an opposing political party, people will tend to project other values onto you that are generally associated with that party, regardless of whether or not you've expressed them.