That Tether expands dollar hegemony is just the story Tether tells the US government to try to convince it not to shut Tether down completely and instead work with Tether to recover dollars backing Tethers in sanctioned wallets. If Tether were backed by another currency, the US government would have less leverage, but it would also be worth less to malicious actors.
The CIA doesn't need to release a PSA to let everyone know of their actions, they have infiltrated SWIFT, have you ever read a join letter between Visa and the FBI?