Actually that is a human right. Countries are free to ally with whatever country they want pending any previous agreements. Eastern European countries made zero promises and had zero obligation to not join NATO. Russia doesn't have fucking "dibs" on them, just like the US doesn't have "dibs" on Canada or Mexico. I wouldn't have a problem with Mexico or Canada willfully joining an alliance with China because that is, in fact, their right to do so. And it would speak volumes to how far relations would have had to deteriorate between them and the US to get there, but that is their right to do so. Maybe if Russia wasn't such a shitty, untrustworthy neighbor, more countries would be willing to ally with them instead of NATO, but hey, that's Russia's problem.