The First Amendment states that the people have a right to assemble peacefully
There is no constitutional right to prevent someone else from express that right. Get real.
Heckling, to the point of disrupting a lawful assembly or preventing other people from speaking, is illegal. It has been litigated many times. Usually comes with a conviction for disorderly conduct.
I heckled B. Clinton once but I did not prevent him from speaking so it was fine. He and the crowd heard me and my cohorts but the event was not disrupted.
Now, if you want to engage in civil disobedience, which is a tradition in American politics, be my guest. BUT you can and should be arrested and you have to be willing to face the consequences. You have to be willing to prevent someone else from exercising their constitutional rights though.
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?