well when I googled “racism in star trek tng” i got “code of honor” so maybe start there
result number 2 was also “code of honor” followed in third place by…well, the 1960s.
4 is code of honor, 5 is ds9, 6 is 1960s, and 7 is ‘beyond the stars’ one of the best episodes of all the treks, but only present in the results because it discussed racism. in the 60s (ok 50s so shoot me).