I think the issue is that the United States – for all its faults and Snowden leaks and whatnot – can still be trusted, somewhat, to do the right thing. There clearly
are trust issues (for good reasons) but I would sure trust the US gov't
more to not install backdoors in equipment private companies deliver to befriended foreign nations.
China, on the other hand, has no clear separation between the state and large private companies, and has a state which does not acknowledge basic human rights in a myriad of ways. Again, the US is not perfect here either, but it sure is better.
Personally, I wish Europeans would use more, well, European equipment for this kind of stuff. This isn't out of some nationalistic sentiment (I have no problems using foreign equipment as such), but given the state of the world's affairs and the direction I fear it might be heading, a strong and independent Europe will probably be more important than ever in the coming decades.