Maybe (just a guess) it depends on where you are? I suspect if you live in a city which leans left, all the people who go with the flow and don't think too much about their views end up being on the left because that's everyone else. The people going against the grain at least have thought more deeply of their views.

And if you live in a majority red community, people who have left views will be the ones who have thought long and deep about their views.