Truth is, they left too much of them alive. Way too much. Would have been better if they just forcibly russified the rest but instead, they let them all live despite being fascists, they let them have their language, their culture, they develpped their country, built factories, hospitals, schools, infrastructure... all that so in the end ungrateful baltshits would stab them in the back. Well either way sooner or later balts will pay for it. They cannot move the land away from Russia.