You forgot that those old Iron Curtain countries requested membership for NATO, so as to prevent future Russian domination.
I think it’s a pretty reasonable worry for countries that have lived under Russian domination for a century to be a bit paranoid about it happening again.
I didn't forget that.
And I understand the motivations.
But the fact remains that NATO's encroachment into the old Russian sphere of influence did fuel Russian mistrust and paranoia.
Truthfully, the end of the cold war was the time to defund NATO and let it die on the vine. It has outlived it's original purpose and has done more damage than good in the last 20 years.