I know a lot of people who are working in collaboration with Chinese universities and does get funded from the US government budget (through NSF and DOE). DOE funds a lot of open research and not only the nuclear/national security related research. I don't think this is in itself a problem. I'm not sure also what is defined as a lie here. Exchanging emails with people interested in your research does not automatically mean you collaborate together. The case is ambiguous, and you shouldn't jump to generalization like that.

There is no ban on collaborating with Chinese universities in the US. There are restrictions for some type of research (that actually extend to the other countries as well).