True-but in fairness, guard members who go on active duty are often stripped of a rank. Guard members don't get promoted based on points-like their active duty counterparts-but on slots available and it can take quite a while to make rank in some units. It would be hard to recruit new guardsmen if they felt that they were always going to be a rank behind another soldier who came from active duty after a short hitch regardless of who was the better soldier. The whole promotions system in the guard stinks, but I don't have any better ideas.
Actually as far as the Air National Guard is concerned, if you're coming from active duty, you don't lose a rank. But yes, if you go to Active from Guard you lose a rank.