[ They are just the old anarchists with some Obama/Clinton rent-a-mob thrown in. ]
The core of antifa is certainly these “black block” anarchists who are a bunch literal vandals who either believe all the crap they have deluded themselves to believe in, or they just want to destroy crap and this give them a good excuse to behave badly because they are “fighting the NAZIs”
Antifa and Nazis both got their start in 1930s Germany. While we are mostly familiar with the socialist faction known as Nazis, the Antifas were a coalition of non-Nazi socialists and communists. Since the groups were essentially rivals, should we be surprised that Antifa thugs behave almost identically to the old Nazis?
The main difference is that Nazis are a joke these days, with few if any followers, and apparently Antifa still has some support.
It is no surprise that the evil old Nazi Soros is now financing Antifa. Nazi and Antifa goals were never significantly different.