I think it was a reaction to fears after WWII and those fears were displaced with a cold war detent.
Which was a "permanent" madness on both sides.
NATO became useful in that cold war and kept it semi-relevant as a so-called defensive/deterrent org.
Expansion of that org. wasn't supposed to be in the cards but it came anyway.
So, Russia got whipsawed by China on one side and Nato on the other while the Soviet structure grew thin.
Whatever they claimed at the start of NATO has long been displaced.
Are they protecting democracy? Hardly. Seems like they want to be big enough to be invincible, though.
Advancing on a sworn enemy over time. Pissing people off.
The more countries they can claim as members,
the more opportunities they can claim they got their noses bent out of shape.
When Peru joins I'm going to start to wonder...
Please seat yourself.
I like the very things you hate.