I think that’s because the “left” states are really just politically center. There’s some that are doing more progressive things like Michigan, but since the GOP is now infected with extreme right goobers, the policies they push are also extreme right, which in turn pushes out anyone center or left of center.

The left analog would be progressive policies that push out the bigots (like Civil Rights and desegregation for trans people), but we don’t have any examples of that these days, since that’s not where any of the democratic state governments are.