It's not against federal law, or the laws of most states, to own a rocket launcher.
A MLRS is not a rocket launcher -- it is self-propelled rocket artillery piece built off the M113 chasis: I'm pretty damn sure you can't go buy an operational MLRS + ammunition carrier + ammunition at the local gun show. An MLRS is colloquially known in the Army as a grid-square remover as it can be fired to kill every soft target in a 1km x 1km area, which happens to be the size of a grid square on a Mercator Grid Reference System map, which is the kind the US Army uses. As far as I know, you can't go buy one. Likewise you can't go buy an A-10 Warthog. You can go buy P-51 Mustang, but guess what? You'll be flying sans the battery of 6 Browning M2 .50 machine guns. Your right to bear arms, a well regulated militia being necessary to a free state, is not sacrosanct. There are already restrictions on it that have passed constitutional muster. Whether an assault weapons ban will pass constitutional muster is beyond my expertise: I'm not a constitutional lawyer. I can say however, after have used an assault rifle extensively, and having fired one in anger on more than one occasion, that they have about as many civil applications as the aforementioned MLRS.
I'd respond to the rest of your points, but I just got home from work, still have some personal work that I want to get done before I get to sleep, and I have to be back at work tomorrow at 7:00am. This supposed pinko commie, who's never known an honest days work or even knows which way to point a rifle, let alone having worn the uniform the US Army, has too much shit to do to waste time "discussing" politics on the interwebs.``