It's actually not. The US government doesn't have to worry about malicious hardware spying on them, because all the hardware is designed (and mostly manufactured) in the US. China, on the other hand, can't trust Microsoft or Intel, so they have to develop their own stuff. Since that's hard, they pawn it off on the Free Software community, who wants the same thing they do (but for different reasons). "The enemy of my enemy is my friend" and all that.