The Russians have been hoping to deter the Poles from adopting anti-nuclear missiles for a long time. They failed, obviously, and have responded with a fair bit of rage.
But Russia's response is not only way over the top, it's reached the pinnacle of silliness. In response to Poland's isntallation of these missiles, the Russians have threatned to nuke Poland.
"If you buy a shield, I will stab you," the Russians say. The only reason to want a country to keep itself from arming with completely defensive measures would be to properly bully them, and the Russians are hoping to continue their bullying power by making it clear that a flurry of missiles could probably overwhelm Polish defenses. But if you are trying to convince a country to disarm its anti-nuclear shield, threatening to nuke them seems like the single worst way to accomplish that. If the Russians have done anything, they have convinced Poland and other nations that the Russians are such loose cannons about their nuclear weaponry that they better all arm themselves with American shield technology. I wouldn't be surprised to see the Czechs and Ukrainians falling in next. Honestly, the Russians are looking like this.
The Russians seem determined to achieve pariah status by doing what they can to intimidate and break their neighbors. Who are we to deny them?