Of course at least some of the Chinese vehicles might meet US standards, but if they are not tested we cannot know. There are some Chinese standards, but I don't know how they compare, and they don't cover all that the US standards do.
It's a pretty complicated and extensive list, including things like door locks, glass, side impact, head restraints, and whatnot in addition to the basic issue of passenger compartment integrity. Of course we're free to think they're excessive and unnecessary, but not to put new cars on the road if they don't meet them.
Of course we're in a sort of cleft stick here. Even if you believe the standards should not be necessary, once they exist, people trust that they are met, and behave accordingly. Meeting them becomes necessary whether or not they should have been adopted in the first place.