I’d interpret that as the state police exceeded their authority by attempting to prevent the attendees hanging out the papers: the police at that point were acting as the government and suppressing free speech.

However, as soon as it was trespass because the attendees had been elected from the event the police were back in their jurisdiction.

While it was within the event it was the shitty ADA having a squabble with some members/attendees. Why the police would get involved in a civil (rather than criminal) matter is a water of their time.