In my two plus decade criminal defense career, I too saw many police reports that parroted the words "loud and tumultuous behavior which caused a crowd to gather and created public inconvenience, annoyance and alarm." Disorderly conduct is what the Boston police used when the City's equally unconstitutional "Sauntering and Loitering" Ordinance somehow didn't fit or wasn't enough. As a new, young, white law student in 1976, I was threatened with arrest by a Cambridge police officer for insisting that he shouldn't be smoking inside the front of the Porter Square Star Market right under the "No Smoking" sign. Unlike Prof. Gates, I swallowed my First Amendment rights and stopped my confrontation upon the police officer's threat even though I knew it would have been an unconstitutional arrest.
As Atty. Silverglate points out:
There is a serious problem in this country: Police are overly sensitive to insults from those they confront. And one can hardly blame the confronted citizen, especially if the citizen is doing nothing wrong when confronted by official power. This is, after all, a free country, and if "free" means anything meaningful, it means being left alone--especially in one's own home--when one is not breaking the law.
See the article also for Atty. Silverglate's brief but thorough history of First Amendment jurisprudence and the evolution of the "four exceptions to the First Amendment's protection for free speech."