Q. Were Miriam and Aaron racists, since they criticised Moses for marrying a Cushite woman (Num. 12)?
An alternative view translates Cush as Ethiopia, suggesting that Moses had a second wife; there is a Midrash that Moses conquered Ethiopia and married the country’s queen.
In any case, God sternly rebukes Miriam and Aaron for criticising Moses, thus rejecting their apparent prejudice against dark-skinned people.
Cushites figure here and there in later books of the Bible: a Cushite informs David that Absalom is dead (II Sam. 18), and another Cushite saves Jeremiah’s life (Jer. 38). The great defence of the Cushites is by Amos, who asks in the name of God, “Are you not as the children of the Cushites to Me, O children of Israel?” (Amos 9:7).
In Talmudic times there was some prejudice against dark-skinned people (e.g. Mo’ed Katan 16b, Bereshit Rabba 60). Noah’s son Ham, progenitor of the Cushites (Gen. 10:6), is thought by the Midrash to have been cursed by being “ugly and dark-skinned” (Bereshit Rabba 36).
But the more normative Jewish view is expressed in the famous passage that relates that when Rabbi Shimon ben Elazar mocked a man for his appearance, the victim retorted, “So go to the Craftsman who made me and tell him, ‘How ugly is this vessel which You have made!'” (Ta’anit 20a-b).
To be biased against anyone for their appearance is thus an insult to God who made us all.