Once a speaker, who has been legally given permission to speak, starts speaking, any attempts to disrupt that speech should be suppressed by the police. That goes for all speakers of all political persuasions.
Agreed, thee is a big difference between a town hall meeting where all should have an equal voice and a speech.
Suppression of speech in a civil rights violation and should be viewed as any other civil rights violation and prosecuted either civilly or criminally. Ones First Amendment Rights ends when one is attempting to violate to rights of others. It a simple equation and one that should be learned and enforced by collage administrations and the FBI Civil Rights Division.