Lawrence O'Donnell writing for TIME:
If the subject does any of those [physically threatening] things, cops always write it out with precision. When they've got nothing, they use phrases that mean nothing.
This was key for me. It's not just that the phrase "tumultuous behavior" is vague. It's that the lack of specifics tells us there were no specifics. In this case, absence of evidence is evidence of absence.
Also:
The president was right when he called the arrest stupid. It doesn't mean Crowley is stupid. It means that, in that moment, he made a stupid choice. Barack Obama has made some stupid choices on occasion too. We all do. Everyone who is defending Crowley's arrest, including his union, needs to re-read his report. There is a crime described in there. In fact, Sergeant Crowley's report is a written confession of the crime of false arrest.
I think this is a very fair take on the situation.