I merely question your claim about Russians having a positive attitude towards Ukrainians and their language. Having subjugated them by famine and other forms of mass-scale terror and murder, Russians allowed Ukrainians to use their language... how magnanimous.
No, there is no comparative study of the effects of repressive policies, because starving millions of people to death and not allowing outside help in (read "The Russian Job" by Douglas Smith) is not practiced on such scale anymore, even by Russia. The Wikipedia page on Holdomor quotes orders to subjugate Ukraine regardless of cost. That in itself negates any notion of Russians having a "super positive attitude" towards Ukraine. Do you know why "(...) you could definitely study Ukrainian in any UkrSSR school from 1960s to 1991."? Because it was not possible while Stalin was alive. It was not possible, because it was Stalin who gave orders to subjugate Ukraine at any cost.
Why would USSR have this famine in Russia and Kazakhstan if the goal was "to subjugate Ukraine"? Indeed why would it even suddenly need subjugating if it was part of Russian state for at least two centuries.
If you have any complaints about Stalin, you can mail them to Georgia, and indeed I'm the first one to do the same.
No, there is no comparative study of the effects of repressive policies, because starving millions of people to death and not allowing outside help in (read "The Russian Job" by Douglas Smith) is not practiced on such scale anymore, even by Russia. The Wikipedia page on Holdomor quotes orders to subjugate Ukraine regardless of cost. That in itself negates any notion of Russians having a "super positive attitude" towards Ukraine. Do you know why "(...) you could definitely study Ukrainian in any UkrSSR school from 1960s to 1991."? Because it was not possible while Stalin was alive. It was not possible, because it was Stalin who gave orders to subjugate Ukraine at any cost.
[edit] more on the history of the freedom to use the Ukrainian language in Ukraine under Soviet rule https://en.wikipedia.org/wiki/Ukrainization