Seriously. This goes for county level too. Lots of people in the county I grew up in seem to think it is deeply red and the only reason Washington goes blue is because King County overwhelmingly votes blue. Trump got 56% of the vote in that deep red county I grew up in which has a whopping 35k people. If you are in a group of people there, a good chunk of them vote blue. And that is not just because of Trump considering it was the same for the governor race. Places are a lot closer than many think.
Which is why a small shift in the number of disaffected voters can be disastrous. You don’t really want 20% of your voting base putting down “uncommitted” in the primary. The number of voters Biden would potentially lose by killing funding for Israel are in areas he is almost certainly going to win by a landslide.