Why do you think the US was so concerned about buying gear from China? They just realized that since they're doing it, China is probably doing it as well.
So next time when they warn about some other danger, I think we can assume they've already done it themselves to others. As for the "IP stealing" that they keep accusing China of, it may be true, but NSA probably steals information from other corporations more than anyone, since they have access to everything, and I'm not so sure China does, too. Most of the world's Internet traffic goes through US, and they have access to that, and as we've seen to the private networks of the world's largest service companies, too, like Google, Yahoo and so on. They also have access to most of Europe's data through UK/Sweden cables. China doesn't have any of this, and could only dream of such access.