If you have another reference to Massachussetts law or any Cambridge ordinances, lets' see them.
All that was required for that turd to be arrested was for him to continue his tirade in a public place, like from his front porch.
He did that.
Also, there were public witnesses to the matter.
Something you have learn as you grow up is that the cops know the laws on these matters better than the criminals and they know when the lines are crossed and they can safely arrest someone. Crowley was not a rookie.