I think much of it is fear.  Both political parties have been selling fear for as long as I can remember.  The Democrats will sell the fear of "throwing granny off the cliff" or "climate change" or "abortion will be made illegal".  The Republicans will sell "they are coming for your guns" or "there is a war on Christmas/Christians" or "that trans person will be in the bathroom with your daughter".  The Democrats sell a fear that is a bit more intellectual, the Republicans sell fear that is more of a visceral fear for many.