This is of course a lie. Th Russian speaking portion of the population was probably greater than 40% or 50% of the population, so "exterminating" it would have been impossible.
In 2014, Russian intelligence services and some Donbas oligarchs allied with Putin bribed, coerced and bamboozled part of the Russian speaking part of the population into separating from Ukraine.
After 8 years of gangster government in the east and experiencing the tender mercies of the Russian military, more and more Russian speakers identify as Ukrainian, for which you can thank Putin.
Says the gangster government cheerleader.