If a large group of innocent US citizens that ventured to China for tourism reasons were shot down by CCP police would you say the government should stay out of it, instead blaming them for trusting China?
if those large group of people agreed to be shot at, for a chance to get a lot of money in return, then they made their own choice and must live with those consequences.
Unless there's some element of fraud undertaken on the part of a national gov't (like CCP), which only the US gov't could present as a counter to, there should be no intervention from the US gov't about the defaults in china and the investment losses incurred to US citizens.