Much depends on what the license actually says. If there's a clause that says that he can revoke your license at any time for any reason or for no reason at all, then this might possibly be legal. Why someone would want to pay for such a license is beyond me.
That said, this guy is cutting off his nose to spite his face.
And this bit, "I want to stress that this license change is not against my colleagues in the USA, but against a small rich elite there that misuses the country's power to rule the world. The USA is our worst enemy,” is the same approach that the "small rich elite" uses to justify the embargo against Cuba, and is just as effective.