He isn’t. Poland is a full NATO member. What the Russian hotheads are saying is that in accepting the U.S. ABM base Poland has just earned itself some pre-targeted instant buckets of sunshine if an all out war breaks out and it goes nuclear. By that time it will be mutually assured destruction and Europe, Russia and North America will all be glass parking lots.
If so, the only question becomes,
1. Are the Russians so dumb they don't understand that this would go without saying?, or
2. Do they think we're so dumb we don't understand that this goes without saying?
Again, your version of what Russia's saying would be like saying if Canada launches nukes against us, we'll launch nukes against them. Such a thing is probably the truth. But so? When was this not true? And why would anyone say this, because why would Canada launch nukes against us in the first place?
Similarly, why would Russia emphasize that if they were in a war (against?) NATO, they would take out Poland's missile sites? so what? and why would "an all out war break out" between Russia and NATO of all things, in the first place? Wars just don't "break out" randomly for no reason, like acne. What exactly do the two sides have to fight a war over, besides Russia's recent idiotic behavior? This still boils down to Russia's paranoia. Poland doesn't want to attack freaking Russia, for crying out loud, and neither do we. Who the hell wants to attack Russia? Who the hell even wants any part of Russia?
Either Russian leaders are very good at bluffing and pretending to be paranoid, or they are genuinely paranoid.
Your interpretation of these statements from Russia is far more innocent (and rational) than the reality.