Take the time to read the article, in it they note origins of antifa go back to between the two world wars.
The initial anti-fascist movements were founded in Europe and North America between the world wars, and were primarily organized by anarchists, communists and socialists – three groups that were frequently targets of fascist violence.
The modern-day anti-fascist movement in the United States, including antifa, grew out of the Anti-Racist Action Network, a decentralized activist movement resisting racist skinhead subcultures and public demonstrations by neo-Nazi and Ku Klux Klan organizations in the 1980s and 1990s.
The Biden campaign ad refers to the Antifa side as a “courageous group of Americans” starting at 1:03 in the ad in your link. Biden never makes any distinction between truly peaceful protesters and Antifa who arrived with guns and clubs.
He goes on to criticize Trump by falsely claiming that Trump was referred to neo-Nazis as “fine people”. In fact this is what Trump actually said: . . .you had some very bad people in that group, but you also had people that were very fine people, on both sides. . . And you had people – and I’m not talking about the neo-Nazis and the white nationalists – because they should be condemned totally. But you had many people in that group other than neo-Nazis and white nationalists.
So in spite of Trump’s specific denunciation of the neo-Nazi groups, Biden falsely claims Trump supports them. He referred to people on the Antifa side as a “courageous group of Americans” without ever condemning Antifa.
Clearly he is including Antifa as courageous Americans, and he has never denied that understanding.
Ya post WWI Germany was a hell zone just gangs of goons fighting each-other in the streets over politics, oddly enough the one party that didn’t really do this the SPD is the only one that still exists.