Well, even if that is true, it still makes them idiots. Anyone who can’t figure out the leftists are not your friends is not playing with a full deck.
There are a number of ways to explain American politics, and the one I like best goes:
Indeed, if you think about it... young people often move to big cities, where they vote Democrat.
When they become successful enough to raise a family, they move to the suburbs, and begin voting more conservatively.
When they've had a long successful life, and can retire to the country, they consistently vote Republican.
Very often it's the same people, same IQs, just with different outlooks on life.
Put another way: suburbs are the 50 yard line, and that's where most of the game gets played.