There's probably some group of network operators out there who decided amongst themselves that it'd be cheaper and easier to squat the dod ranges when shuffling traffic amongst themselves, than having to wrap each packet with a tunneling header. Or who knows maybe some third world dictator told their isps to use the dod ranges because they mistakenly assumed it would isolate their nation's traffic from the rest of the world. It's a real shame that the linked article doesn't divulge what's actually happening.

The DOD owns all IPs starting with 6, 7, 11, 21, 22, 26, 28, 29, 30, 33, 55, 214, and 215. To a network operator who spends his day filling out forms explaining why he needs each and every /32 I imagine it must make you feel like someone who spends half his income to live in a tiny crumby apartment in a city surrounded by vacant unsecured mansions. The owners of these mansions haven't set foot in them for thirty years. So surely it must be safe to just move in right?