As soon as Poland had a chance, they wanted into the EU or NATO, preferably both. They, Poland, desperately wanted in. Why? Because they wanted protection from Russia, and with good historical reason.
Estonia, Latvia, and Lithuania? Same story. It wasn't that the US had a nefarious plot to ensnare the border countries in a US-dominated alliance. They desperately wanted in, because they have experience with being overrun by Russia.
If Russia doesn't like this, maybe they should work on making their neighbors not feel so afraid of Russia. Things like the Ukraine and Georgia? They are not helping.