The Russias threatened war with the US a day ago and threatened nuclear attacks a day later. Trump is well within his right to hit Moscow today as far as I’m concerned. Responding on truth social is definitely within the realm of reasonable.
I doubt that Russia cares what Trump says...they’ll simply RESPOND to actions as required, and the fact that they have the tools to do so doesn’t seem to bother the Neocons that Trump is now parroting.