I agree the military wouldn't be the ones shooting people on sight or rounding people up for internment camps, at least not the military I served in. Most of the Marines I served with are moderate to far right conservatives and would never fire on Americans.
But, with that being said, I think many of us were surprised at the number of National Guardmen (U.S. Army for all intents and purposes) who took part in rounding up firearms and arresting citizens who refused to leave their property (or who refused to surrender their firearms) in NOLA.
I was also shocked/pissed at the number of LEO's who willingly went to NOLA to enforce unconstitutional orders given by the state government.
So who knows... perhaps things have changed enough to where a good number of those in our military would fire on citizens or round them up... God only knows they should have known better in NOLA.
I'm going to have to differ with your opinion here. The LEOs I knew who talked about going down to NOLA were going to stop the supposed "looting" and help enforce the law, not to disarm the citizens.
Additionally, with the news coverage making things sound much worse than they actually were (go figure) when the Governor declared martial law, it's not surprising that the Guard was willing to obey orders disarming the citizens who were supposedly shooting at them while they were guarding against looting. I don't condone those actions, but I'm not surprised by them.