Comparing the cops at an Occupy event to the SS is despicable, even for you.
An arrest is the use of force. Dragging them away is using force. Any physical contact is force. The cop was going through a standard escalation of force, from the least physically severe to the most. If the protesters had moved when ordered, they would not have been sprayed. If they had moved after being sprayed, they would not have been manhandled. If they had moved without being physically forced to move, then they would not have been arrested. You don't get to decide what laws and police instructions you feel like obeying, just because you're a malcontent.
I'd like to see more on this guy's service record before I accept your word that he's a vet, and even if he is, the minute that he breaks the law, he abrogates any consideration for his veterans' status. Our uniform isn't a license to break the law, in fact, it demands that we follow it. Using his status to justify his behavior simply makes the rest of us look bad, which, of course, isn't an issue for you so much as a perk, but we don't care to be associated with him, thank you very much.
You obviously didn't watch the same video. I saw him facing off against a single cop who was in advance of the line, repeatedly disobeying the hand gestures to move aside. No audio, so we don't know what he said in response, but we can see him shouting. As for why they didn't just use 2 cops to arrest him, they don't do that because using too little force is dangerous for the cops, as well as the perp. A larger group is more likely to overcome resistance quickly, while a pair of cops is more likely to get injured or have to cause injury in subduing the perp.
I saw an individual facing off with a police officer who repeatedly gestured to him to move aside. The stance was belligerent and aggressive, and he continued to face the cop and, at several points, crouched into fighting stances. Also, I didn't get any audio, so we don't know what he said to the cop in response to the lawful order to move, which means that any provocations or threats are conveniently left out. Given what we know about the violence of the protesters, their despicable and vile conduct towards the police and the overall level of anarchy that they have fostered, you're going to have to do better than this.

