The photographer is shooting at a refinery. A cop shows up and asks what the guy is doing. Guy says he's an artist. By the guys own admission, the cop was perfectly friendly and polite. Cop asks to see his id, and gives some spiel about how Homeland Security lets them require you to show your ID. Cop runs his license and hands it back and says he can keep on shooting. Cop leaves.
There are two things going on here. First, nationally in some areas there's this push by law enforcement against being photographed, and they try to extend that to public places too. That's very bad and needs to be combatted.
The second thing is the flavor of this article is trying to portray this event in the light of the first situation, and it just plain isn't. If anyone is taking pictures of a major installation and it's not something that normally happens, it's prudent to just nicely ask what the person is doing and move on, which is what happened here.
The photographer wasn't physically detained or arrested. The cop didn't want to look at the photos or try to make him delete them. Just because you feel like you are being detained doesn't mean you are.
I am a photographer too. I got all bristly when I first started reading this, only to reach the end and see that nothing happened. I've gotten face to face with people who think they can can control what people take pictures of.
This, however, is not one of those situations.