In general I'm not a fan of statements in the form "The only time I'm in favor of (insert reprehensible thing you're opposed to) is when (whatever)." I find them squirrely and annoying and, y'know, morally inconsistent.
The only time I'm in favor jailing anyone is when it's cops who beat civilians. Unfortunately, these are among those classes of people, and classes of actions, that will never be punished by jail time. Unlike, say, the action of being beaten by cops, which quite frequently is so punishable.
(And yes, these comments are inspired by it happening to someone whose work I admire [read the comments], someone who is a type of person--middle class, middle aged, and above all white--that this does not normally happen to. Please do not take this to mean that I only care about it when it happens to this kind of person. To me, the assumption that cops are evil assholes who deserve whatever they dish out to return to them twelvefold is as basic as the assumption that I need oxygen to breathe.)
Also: a lot of people, any time any incident like this makes the news, will immediately start going "Oh, well, we don't know what happened, let's give the cops or border guards or whatever the benefit of the doubt, he may have provoked it." Which is bullshit.
Reason this is bullshit #1, this specific case: I concede that there are occasions when one human being can be considered justified in punching another human being in the face and using pepper spray on them. I will concede also that there may occasionally be cases where it is justified for several people in a position of authority to do this to one person who is not in such a position, though we are already on extremely shaky ground with this. What is never justified under any circumstances whatsoever no matter what is releasing someone, vehicle-less, without a jacket, into a winter storm, forcing them to walk across the Canadian border, after public transportation has shut down. This strikes me as attempted murder, frankly. Even if nothing else, and that's a big even if, give the man his fucking coat.
Reason this is bullshit #2, general rule: In all cases of dispute between two parties, the default position should be to suspect the worst of the party with power and the best of the party without. Not only is this the safest assumption based on the evidence of all human interaction in all of history, it is also the fairest. The party with power already has power; don't give them more by giving them the benefit of the doubt. Never give power the benefit of the doubt. Ever.