Court and other official documentation had to be in Ukrainian language with possible translations to Russian as separate documents, it's not that big of a deal. In common life, there were no restrictions at all and everyone could freely use russian language. And yeah, some people were upset it wasn't recognised as the second official language besides ukrainian.
As for Donbas, it was our territory, controlled by some shady people with questionable past and informally supported by Russia as a buffer zone with pro-russian people.
How is it different from your conflict in Chechnya, for example? You said there were terrorists?
Well, we said the same about militia in Donbas.
Chechens wanted independency?
Donbas too, but you still bombed Chechnya and killed around 250 000 chechens as far as I remember.