Don’t entirely agree with you. Carried to its logical conclusion this principle would justify Russia re-invading Poland and the Baltics, possibly more.
But I do find it interesting that the very people who decry our being “policemen to the world” seem to automatically assume it’s our business to stick our noses into this situation.
Russia’s interests in Poland and the Baltics are balanced against those of Western European nations which also share their borders. Ukraine is clearly beyond the scope of Western Europe, and has always been within the Russian sphere. To NATO, Ukraine is “a bridge too far.” To Russia, Ukraine is a strategic necessity.
I do realize that the Baltics do not border Western European nations, only Poland and Russia. But they are much closer to Western Europe, and more directly affect its strategic interests.