The first way you are treated is what you become in a way. When you get to the border and they are searching your car, you are guilty until proven innocent. And I argue it should be that way.
Think of the ramifications of seeing someone in a car at the border and treating them cooperatively. If they are a competitor intent on blowing the place up, then the guards have a lot to lose in this prisoners dilemma and little to gain. They could lose their life, but they gain a happy dude who got through the border easily.
Unfortunately, in this case, the individual crossing the border when treated like a guilty person didn't appreciate it and things got out of hand. That much we know. That's not the desired outcome, but what was the worst that happened? He got pepper sprayed, roughed up, but lived to tell the story. If the other team had lost, they could be dead -- lots of them could be dead -- or even worse, a city blown up. Dramatic but true.
So, let's all try to understand that we are all in this together. I really don't think some border guards are looking forward to beating up a sci-fi writer and I don't think the sci-fi writer was looking forward to experiencing anything even close to what went down there that day.