It is so simple.
The first few thousands of anointed ones were Jews who apostatized themselves by joining the sect of the Nazerenes.
During the dark ages a few Christians who fought the Trinity teaching and papal indulgences, etc. were anointed.
Finally, in the 19th century the remainder of the heavenly calling were chosen from among a group of serious Bible students largely located in the northeastern United States. The women wore pill box hats and the men were in their "Sunday best." They attended religious conventions where they were taught, among other things to "Advertise, advertise, advertise the King and His Kingdom."
Some of these anointed proved unfaithful and were "lopped off", replaced largely by mentally unstable, egocentric undeserving wackos who had only in recent years become members of Jehovah's Witnesses. Two or three of these were black.
Obviously, this was all God's will.
tms