So you're saying Ukraine should have given up its sovereignty to please a hostile neighbor? That logic justifies any invasion by a stronger power. Should Finland have said "no" to NATO so Russia wouldn’t feel "threatened"? Should Poland have surrendered in 1939 to avoid casualties?

Ukraine was not joining NATO when Russia invaded in 2014. In fact, Ukraine had declared neutrality in 2010. That didn’t stop Russia from annexing Crimea and fueling war in Donbas. NATO wasn’t pushing Ukraine—Ukraine sought NATO because of Russian aggression.

Your U.S.-Mexico analogy falls apart because NATO is a defensive alliance, not an expansionist empire. Meanwhile, Russia does invade its neighbors and claim their land. If Mexico were invaded by a dictator who called it "historically American," would the U.S. stay out of it? Didn’t think so.