> At one point someone tried to rush the stage, though we don't know his motivations. That person was beaten, which should have resulted in the arrests of everyone involved.

The person who rushed the stage was Isadore Greenbaum. All he did was shout "Down with Hitler!" and knock down a microphone[1]. He was the only one arrested and was further charged with disorderly conduct[1]. None of his assailants were charged or arrested.

1. http://www.historynet.com/made-in-america-americans-in-suppo...