He certainly doesn't beat around the bush here. Very nice too see someone of his stature stand up and call out these shenanigans for what they are.
I see what's happening now as game-theory signaling, not as a real threat to Powell. I would suggest that this action is better seen as a latent threat to the next Fed chairman to let them know that they will either enact Trumps desired Fed policies or they will be prosecuted for anything that the administration can manufacture.
It's also important to remember that Powell is not the only Federal Reserve Board of Governors to have very odd accusations of wrongdoing and investigations launched. He's also done this with Lisa Cook. It seems pretty blatant at this point what's really happening.