It's not an American thing. The same issue crops up in the UK with London, for example. If you move to London you know you're going to be hit by things like ULE

It's not an American thing. The same issue crops up in the UK with London, for example. If you move to London you know you're going to be hit by things like ULEZ or endless ideological propaganda ads on the public transport system because of how the people there like to vote. If you move to a village in the home counties you're going to have a very different set of experiences. In the UK this is often disguised because it gets conflated with age: people want to live in the big cities when they're young, and when they're young they're more liberal. As they got older they get less liberal and want more space, so move out of the cities, so at no point does it feel like they're selecting where they live based on politics. But it does shake out that way regardless. The USA is big enough and California far enough to the left vs other places, that even moving from one big city to another will yield noticeably different neighbourhood politics.