The difference is that they're all on side except the biggest and most dangerous. Nobody can blame the Poles for being very wary of Russia and its allies.
At this moment circumstances puts Serbs and Russians on the same side (we faces same threat). That gives pretty clear signal to Poles that right now, they don`t need to fear from Russian invasion. It is so because Poles and Serbs represent traditional historical partners. Even more, Poles and Serbians are to each others good loyal brothers. So, even if no other reasons not to confront Poland, at least- Russia won`t dare to risk her relations with Serbia.
Even involvement of Serbs in Ukraine, gives guarantees for satisfaction of Polish interests in the region, on the long run. Yes, i am quite sure that i speak truth when say that are Serbians guarantors of Polish eastern borders. That is something what NATO can`t offer to Poland. Never. On the contrary
Actually, Polish people, intelligentsia and politics already realizing that Serbian challenges must be seen as Polish challenges, if Poland wants to survive.
necessary to be said here.
At this moment of history Poland and Russia are very mutually interdependent.
Till now, in history, Poland may benefited from weak Russia and/or opposite, Russia may benefited from weak Poland. Even then, neither Russians, neither Poles wanted total destruction of the opponent. It is because, no matter their mutual antagonism, they were aware of the extremely aggressive foreign, non-Slavic, factor on both- Poland and Russia. That is situation that exist now too, with further straightening of factors that increase mutual interdependence. Greater danger for Russia, Poland would feel more endangered. Not from Russia but, in case that Russia collapse. It is so, because without Russia, as factor of balance in Europe, same factors that could eventually destroy Russia, after finish with Russia (as if), would inevitable turn to finish with Poland. Reason would be invented in the blink of an eye.
And so, interdependence rising. Why would then Poland want to end this situation and give contribution to the destruction of Russia? For sure Poland won`t do that. Especially, ESPECIALLY, when situation qualitatively dramatically change with every new day and, when now Russia starting to have interest in strengthening of Poland in Central/Northern Europe, same was as profit from strengthening of Serbia on Balkan/Central Europe, as well as, let us also underline, from strengthening of China in Asia, Brazil in Latin America, etc, etc.