There are a lot more Republicans who are quite literally neo-Nazis than there are Democrats who are communists.
Name one. Just one. And list the specific National Socialist policies he or she advocates - not just the usual “But his budget cuts are mean to protected groups!” nonsense that usually triggers the Nazi slur.
Any number of Democrats - Sanders, Warren, Pressley, Tlaib, AOC just to name a few - are unabashed Marxists who would have been thrown out of the Democratic Party of John F. Kennedy.