I have moved on...I just will chime in whenever german history is being downtalked and denied in those lands.
well, it was a Polish mistake to propose it, but the plebiscite included emigrees from the area to central Germany - almost all of them voted for Germany
between 1895 and 1919 335 thousand Germans settled in the area (from other regions of Germany) - they were either economic immigrants or state officials (they mostly settled in the cities I presume) - in this sense they wouldn't be called ethnic minority in Germany now - would they??
large part of those who voted for Germany were not German nationals (their mother tongue was not German but Slavic) - they simply did not identify with the Polish statehood (never knew any etc etc) and perhaps even Polishness for various reasons (though their speech was actually a Polish dialect) - this is shown anectodically in stories where brothers were fighting opposite sites in the "Silesian Uprisings"
the plebiscite area was under German admnistration and German police and para-military organizations were present