The article said that he was selling radio equipment. I’m sure all of the buyers will be getting contacted and investigated to ascertain if foreign buyers were involved.
Many 'military' radios are commercial or have nostalgic value. The article is short on details, and given the spottiness of the records of this unit (obvious they aren't tracking property as required by DoD policy considering this was allowed to occur) it's entirely possible this guy just owns DRMO'ed equipment himself he buys/sells. Take that out of the mix, and the rest of the 'evidence' point to this being an overworked sysadmin/engineer who takes his work home with him. It's a common occurrence in every workplace even the DoD; many of the NSA leaks is from individuals trying to work on their personal computers at home.