In 1990 Ukraine was part of the same country as Moscow. The USSR had already carried out their programs of ethnic cleansing in Ukraine in the early part of the 20th century (see also the Holodomor and the general scourge of communism).

It'd be a bit weird if they felt a need to culturally reshape Ukraine again after only a few decades of independence. I'm going to be sceptical there is a "cultural genocide" going on here beyond the usual horrors of war and occupation.