[Cheburashka]

I agree with you that recalling something done in the 30's is unfair. The Russia of today is not the Stalinist state of yesterday.
But if Russia and Ukraine have a contract for gas at $50, Russia is entitled to $50, whether the present market price is higher or lower than $50. That's the point of a contract. If the market price was $40, then the Ukraine would still have to pay $50.
If Russia withholds gas that it agreed to provide for $50, then Russia is breaking its word, its contract, and some people would say that Russia is stealing.

[RusIvan]

If Russia withholds gas that it agreed to provide for $50, then Russia is breaking its word, its contract, and some people would say that Russia is stealing.==

The problem is that they no conract for $50. They just lying about thier own people.
Just test. Let them go to court if they have such conract. They will not. Since they have not it.