Mongrel as a word to describe humans of mixed heritage has a long and not very illustrious past.
‘Americans are a mongrel people, half Jewified, half Negrofied’ Adolf Hitler
"I will never fight “with a Negro by my side. Rather I should die a thousand times, and see Old Glory trampled in the dirt never to rise again, than to see this beloved land of ours become degraded by race mongrels, a throwback to the blackest specimen from the wilds.”
-- Robert “KKK” Byrd
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"Americans are a mongrel people, half Jewified, half Negrofied"
-- Adolf Hitler
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"We are sort of a mongrel people."
-- Barack Hussein Obama
Just the ‘phonetic sound’ of the word ‘mongrel’ has a repulsive aura about it. A more ‘vanilla’ word to infer could be ‘hybrid’ although its technical meaning does not involve humans whereas ‘mongrel’ is an appropriate and correct term for human interracial mixing. It is what it ‘bees’!