NOBODY was keeping Rooty from speaking, you are delusional if you think they were. Noise DOES NOT prevent a person from speaking.
Rooty Toot was riding in a parade, are you going to sit here and tell me that nobody else along the parade route was shouting things?
Again, if you disrupt a lawful assembly of people exercising their own constitutional rights then you are engaging in illegal conduct.
From the facts contained in the article they made it impossible, impractical or both for Guiliani to speak.