They should be called Nazi's. Some left-wing nut job calling people fascist is an old trope. People can ignore it because they've seen it on TV a thousand times, it's a joke. Calling someone a Nazi on the other hand isn't used for a joke nearly as often. It's much more difficult for a layman to ignore. So while you are technically correct that calling them Nazi's is not the correct use of that word you don't get to decide what words we get to use. That is decided by the zeitgeist and social consciousness and calling MAGA followers Nazis is what's cutting through the noise.