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.

For details and links see: