It doesn't make sense that Russia would be interested in Poland. Of all the former Soviet block nations they would present a gargantuan challenge not only in taking over but also in administrating. Even if there wasn't a NATO alliance.
It's complicated. How Russia views Eastern Europe is a big stewy mix of old historical ethnic conflicts going back to the Tsars, areas that Russia always considered to be their "area of influence", ethnic Russian minorities that need to be "protected", (regardless if Stalin put them there or not to displace other peoples...) their experiences in WWII of being invaded, Putin maintaining external crisis to keep power...
Since the 1900's Americans largely view "war" as force projection, something that has to happen a long way away. Russia on the other hand views "war" as "they just start marching over".
I can only go by seat-of-the-pants feelings on this, but IMO, Poland is by no means in a "comfy" place, but they at least check off fewer "Is Russia Interested?" boxes on the checklist than the Eastern Ukraine, Estonia, or Georgia does.
I would be a bit concerned if China started exerting overwhelming influence in Mexico and central America. If China started the process of economic colonization of our southern hemisphere one could argue that it could be a potential threat to our national security.
That too is a fair point. As Americans with 100+ years of mostly peaceful coexistence, and relatively stable nations (Mexico? At least in comparison to many other places in the world it is...) on our borders and buffered by oceans to the East and the West. And even "our area" of Manifest Destiny in the Western Hemisphere... most of it is largely all the way below the equator, and just as far off. So on a gut level Americans tend to be a bit myopic about how other nations view things. Even if we find the nation to be ideologically "wrong" or whatnot, there's still a more fundamental level of "means, opportunity, motive" etc. when you've got a bunch of different wildly diverse places on your borders.
How Russia "feels" as a whole is how America would "feel" if instead of just Canada on the north, and Mexico on the south, we had several smaller alternating "Canadas" we trust, "Mexicos" that are a PITA, but mostly ok", AND a "Russia" and a "China" on our borders too.
So it does put us in a position to be viewing things at cross-purposes. Russia as a whole may have genuine beliefs about its security, that we'd view as expansive/aggressive etc. So, I won't say I'm "sympathetic", but I will say I can understand that Russia might have rational motives for what they're doing or might do from their perspective.
Although there still is the most basic standard, either you're violating some other nation's sovereignty or you're not.
