Those are all words that corrupt or renegade police officers use to pretend they are giving reasons for an illegal arrest or other illegal conduct?

What does "argumentative" tell us about what the the traveler actually did? Does it convey any information about any physical movement, speech, or sound initiated by the traveler?

What does "aggressive" tell us about what the the traveler actually did? Does it convey any information about any physical movement, speech, or sound initiated by the traveler?

What does "obstructing" tell us about what the the traveler actually did? Does it convey any information about any physical movement, speech, or sound initiated by the traveler?

If I say someone was "argumentative," "aggressive," and "obstructing," tell me ANY information about ANY action they performed that led me to characterize their actions. ACTION THEY PERFORMED, not my opinion of it, or a value I attach to it, or want others to attach to it.

The agent is saying "this traveler did something, but I don't want to tell you what he did, and I decided I wanted to order him out of the car, and I know the law uses words like "argumentative, aggressive, and obstructing," so I am going to say his behavior can be characterized by those words.

Somewhere in the conversation they accused him of "threatening a Federal officer." I didn't listen to the whole video, but did he "threaten" to commit ANY ILLEGAL ACT?

I went to an immigration conference once and one of the speakers had a client coming in from Canada, I think, maybe he was driving him in, I forget. Anyway, they said to the client to go to some office and I think drove him over there, and then the attorney was going to drive over, and they said they wanted to drive his car over there, he said no, I'm a U.S. citizen there's no question about my right to be in the country. They said, we can pull you out. And he said, "if you think that's a prudent thing to do, that's what you should do." The head of the checkpoint came running out and said "Tywin!" ["Tywin" wasn't the speakers real name; I'm using a pseudonym], what are you doing, and he said ask them! They have no right to drive my car if I don't consent, etc. And the head of the checkpoint sent then back to wherever they were supposed to be and everything was OK after that.

This guy said the checkpoint booth people are generally young and don't have the sophistication to interpret subtleties of rules; they are given rules that are like flowcharts, sort of.

But the typical traveler doesn't know that; they expect the booth people to ask questions that make some kind of sense and are likely to be nonplussed when an agent asks them to specify the stores in which they are expecting to go shopping.

And of course, some of them are dishonest and corrupt, and pretend that any kind of questioning of what they said is a questioning of their authority and therefore a threat to the USA. But it's their job to actually protect the US, not to harass travelers who think (correctly) that the question they are being asked is stupid.

I think you do know, which is why you are uneasy about the agent's behavior. The agent knew as well. "Aggressive, argumentative, and obstructing," are not descriptive words. And then all this talk about protecting the USA and Canada. "My job is to protect my country, so I should be allowed to do anything I want."