> As far as I understand it, he laid hands on the officer, then struggled against arrest.
That's not how I understand it.
> Supposedly one of the videos shows him reaching for some black object. I don't know.
It would be good if you'd watch this review.
The very start of the incident is an officer chasing a woman, she slips and falls, the officer chasing her catches up and then Pretti pushes the officer away.
So I checked it out, but it's not really relevant. These activists appear to have followed the federal law enforcement. That highly suggests they knew exactly who they were. The officers didn't show up unannounced to the front door of someone who happened to be an activist. No reasonable court is likely to determine that they were unaware who they were dealing with.