Answer:
He was motivated by their constant refusal to obey his political and ideological beliefs. There were many famous writers, scientist and scholars who were opposing him. Many of them fled and were exiled throughout the world, but some were not so lucky.
Step-by-step explanation:
Stalin's regime was totalitarian. He didn't accepted any type of political opposition. Not only that, but also those who weren't ready to follow his ideological beliefs were persecuted. Probably the most famous example is a Nobel winning writer Alexander Solzhenitsyn.