A month ago someone here suggested the hilarious theory that Tether is being used for crime in a way easily traceable by the government, so certain agencies are propping it up so they can keep the operations going. Meaning that the criticisms a) "Tether is insolvent" and b) "Tether is used for crime" effectively cancel each other out...
https://news.ycombinator.com/item?id=32588210