It's interesting in itself that they choose to announce it. It's a soft declaration of war of sorts really and perhaps another step along the line to preparing their populations for open war with China (and perhaps Russia too at this point). They claim they're "hitting back" despite clearly hitting first but perhaps that's part of the plan too.

Good to point out that they've also publicly announced recruitment of spies from Russia and China with slickly produced, very publicly disseminated videos on social media trying to recruit people from both nations as well as open statements by US intelligence leadership that they're stepping up recruitment and targeting and claiming they're not meeting goals (never trust a liar). So they're very much making this an official cold war at the very least if not paving the way for stepping up to a hot war in future from these open acts of aggression.

Part of it may be messaging, they want the public, they want Hollywood "thriller" writers and such to notice these things and make more anti-China, anti-Russia content and for there to be this undercurrent of a sense of we're at war with China and Russia.