I'd say the main issue is your painting of the political sides.
You point to ideologies, not actions, to define these parties.
I'm not even sure it's anarchists vs fascists.
For me, the primary issue is simply the actions taken.
I don't care who you are, I don't care what you believe.
You could be a black radical neo-nazi campaiging for anarchistic islamism, you could be a white racial oligarchy campaiging for some grand pyramid of social hierarchy set in place by machines.
It makes no difference as to whether or not the actions taken are wrong.
If someone attacks you, there's nothing wrong with responding in kind.
I don't care their politics. Their politics are irrelevant.
The aggressor is the one who commits an immoral act. Whether the individual attacked is hoping for it, planning for it, whatever, the immoral act is that first punch.