That is pretty much the meaning of “fascist” these days: Someone the Left doesn’t like.
The Left is now so far Left that anyone to the right of McGovern is the far Right to them.
It’s why Bernie no longer has to pretend he’s not a Democrat so he won’t hurt them at the polls and why these new pups who don’t feel the need to hide who they are anymore are giving the old wolves (who still want to pretend they aren’t Mensheviks / Bolsheviks) fits.