Also, someone fact check if im wrong, bit i am sure the Antifa flag is very similar to that of a flag used by the Nazis.
In any case, both groups, especially AntiFa are using tactics that the Nazis used back in the 30's, 40s - book burning (statue toppling today, but also the cancel culture of 'burning' books and movies that they dont like) ; stopping freedom of speach, going after religion, being violent etc.
Antifa's flag is the flag of the communist party in Germany.
Fascism and communism were fighting over Germany. They both wanted to overthrow Germanys old system and democracy. They both used radical tactics. They were polar extreams with similar outcomes. (Ex Linine/Stalin after WW2) that was the communist side.