With few exceptions, it is legal for non-felons to own personal body armor. In my experience, US Cavalry won't sell anything but cheap t-shirts and plastic AA battery flashlights to anyone but LE. That's company policy, it's just more of a super-CYA stance. They'd hate to see a pair of quality binoculars fall into the wrong hands (i.e. anyone non-LE) and God forbid a lowly civilian gets a hold of a nice pair of boots... oh the horror!
The Point Blank Interceptor issue has to do with the armor being possibly stolen rather than whether armor itself is legal to own. The general consensus is that not all PB Interceptor vests are stolen US military property, but there are enough of them that the DOD is considering all of them stolen so unless you want to go toe to toe with the feds in court over a $400 vest, avoid those vests.
Body armor is a defensive tool, it has little to no offensive capabilities. Well, maybe some of the older, heavier vests would hurt a bit if you got one whacked across your head, but it's silly to restrict them. Just the other day I was in a local gun shop, one that will happily sell you an AR, AK, Glock, .50 BMG, etc. with as many magazines as you can afford, plus a few thousand rounds of ammunition as long as your cash is green, but don't even ask about the level IIA Kevlar vest they have on display. That is too dangerous for civilians to possess, they would never think of selling it to anyone but a cop. Pretty silly IMO.