I think people like to put everything in the same bag, put a tag on it, and forget that they were not the same to begin with.
I mean, sure there exist both "left" and "right" that is not full of extremist assholes.
But there also existed extreme right that were just a bunch of irrational assassins (think Nazi Germany), and extreme left that again were a bunch of assassins too (think Stalin).
I think right now in the USA you have the full spectrum, and if the right or the left don't want to be mixed up with the others, they should call them out.
To be honest, I think your President, being himself clearly from the right, made a terrible political mistake on not calling out the extreme right on time, making it clear that the right is not the same... Or perhaps he didn't, and he actually supports the extreme right for real.
Of course the left should also call out the idiots from the extreme-left, or else it loses credibility. IMHO.
PS: But considering their positions, goals, support and chantings, I would be more afraid of what the extreme-right could lead into right now. Of course, IMHO.