If nothing makes USDT or Tether illegal I think they can provide valid shreds of evidence in the U.S court and I can also say that this is a piece of good news to say that USDT/Tether is clean when it comes to legality.
But if what they show they need becomes invalid in the U.S. court, it will be a big problem for sure. I just don't know if the bad news about the dollar is related.
Anyway, you should just chill and relax as far as I can see everything will be fine for usdt/Tether.
I would say that there is "some" illegal parts of it. Not because they are doing anything unethical or just scamming you, they could be legit and decent and still be found guilty, not for like a jailed type of crime, but for some SEC crimes which are related to finance and could be punished with just a fine, which could be millions of dollars but fine.
They have billions, tens of billions of dollars from us and gave us something they created themselves out of nothing, that could always be troublesome in a court of law and that would be the case they are going against. Doesn't mean they have ot be scammers, just that idea alone is a risky one.