+ Romania
https://www.youtube.com/watch?v=g1Q6DF8TmjM
Maybe Ukraine, Belarus is a different story, vast majority of Belarusians speak Russian today, not Belarusian.
So do people from Ireland and Britan, Austria and Germany, R. Moldova and Romania, etc.
That doesn't grant the bigger party the right to question the sovereignty of the smaller one.
It is up to the people to decide, ideally in a referendum that is declared valid only if the voter turnout is >= 2/3rds of the voting age population.
Because right now in R. Moldova it won't pass firstly, but secondly I doubt that the political class in Romania wants us as another burden on their social system. Those from the political class in R. Moldova also don't want to lose their privileged access to the resources that enable them to steal. Simply using the hype (or fear) to rile up the voters in both countries is a good status quo for now in both R. Moldova and Romania.
It is just politics. Ukraine and Belarus are more Russian than many of the regions and republics of the modern day "Russian Federation". Better Ukraine or Belarus would be in Russia instead of Chechnya or Dagestan. But the russian government did many stupid things to piss off Ukrainians and ruined any integration processes in the long term. Also Russia as country with a mediocore and corrupt economy is not anymore attractive to young super-westernized Ukrainians and Belarusians who grew up with western culture and are aware of the much better economy in the West.