So first off, Ukraine couldn’t have joined NATO because of the active territorial dispute re: Crimea, which had been ongoing since 2014. But more importantly, please for the love of God stop following the cold war colonial logic that only Great Powers have any agency in their own international affairs.
Poland, Lithuania, and all the rest of the countries that Putin wants out of NATO are in there because they wanted to be, mostly because they wanted security against Russian invasion. Like, Poland basically blackmailed President Clinton into expanding NATO by threatening to support the Republicans in the next election.
But why would anyone be worried about Russia invading them if they tried to exercise independent agency and leave Moscow 's sphere of influence? Oh wait, look at what’s happening in Ukraine. Maybe those fears weren’t so unfounded. Sweden and Finland certainly seem to think so, since the war led to the most significant expansion of NATO in decades and gave NATO a direct land border within spitting distance of Moscow.
Would you believe that there’s a racist element to this as well?