IMO, Arnett made a calculated self-serving move. Yes, Iraq military was there, and he had to be careful what he said. But I don't believe he was forced to give the interview, i.e., he could have stuck to reporting his observations as well as his minder would let him. I think he was sucking up in order to be freed from a minder, so he could get stories his peers could not (or, so he could make up stories, as is his wont, e.g. US use of poison gas on its own troops).