Well, you certainly can’t just look at or listen to people over there to determine their origin or loyalties, particularly in the eastern part of Ukraine. Many people there speak Ukrainian and Russian equally well, with an indeterminate accent.
The drive is to root out Russian spies from Ukraine’s military. Russian puppet Yanukovich was in power for the past 4 years and his promotion policy was likely friendly to those having their loyalties with Himself and Russia instead of Ukraine.
“Well, you certainly can’t just look at or listen to people over there to determine their origin or loyalties, particularly in the eastern part of Ukraine.”
That is certainly true. There are going to be many an official of otherwise impeccable background who is covertly a dedicated Marxist, Leninist, Communist in sympathy with restoring the Soviet Union and expanding it.