[vkou]

> How is NATO expansion eastward scary or destabilizing for them?

It's scary and destabilizing in the sense that Uruguay doesn't really give a rat's ass about where the borders between east and west are drawn in Europe, but would really, really, really prefer that NATO and Russia don't get into a shooting war.

Same thing with threats to the MAD balance of power, like anti-missile defenses. Anyone standing on the sidelines doesn't really care about where the borders are, they just don't want one side to scare the other to the point of nuclear war.