I caused quite a stir in the days after Charlottesville when I declared that the alt-left is just as bad as the alt-right. I wasn't the only one to say it, of course, but all of us who did were lambasted on multiple fronts for having done so.
One argument was that the alt-left doesn't exist at all, in the sense that the alt-right is an identifiable group of people who chose that name for themselves, whereas the alt-left is just a collection of concepts and movements whose only common thread is that people like me don't like them. Another argument was that the alt-left has no web site, no leadership and no statement of principles. Still others said that because the white supremacists of the alt-right sympathize with Nazis, who committed the Holocaust, it's not even possible for anyone else to be as bad because no one has done anything as bad as the Nazis. (I'd make a case for the murderous 74-year reign of Soviet communism but for now I'll just note the point being made.)