It relied on slaves to produce cash crops
Answer: Reason
You can read about that on wikipedia: https://en.wikipedia.org/wiki/Age_of_Enlightenment
Or here on history.com: https://www.history.com/topics/british-history/enlightenment
There are two interpretations of this:
1) It was a "gift" to Ukraine, marking the amicable relations between Ukraine and the Soviet Union, to bring them even closer
2) It made the Ukrainian Soviet Socialist Republic more ethnically Russian; which would shift the dynamics in it and tie it even closer to Soviet Union (And for example make it less likely that it would try to split )