I find that odd since Moses took a Cushite wife (African), Joseph married the daughter of an Egyptian Priest. Israeli Kings took foreign wives, Abraham married Keturah, a non-Jew. Jews also married into Canaanite families (take Judah for instance).
The descendants of Keturah became the Midyanites, Israel's enemies. Even after Sarah's death, Elohim honors Sarah, and ONLY Sarah as Abraham's one and only legitimate wife, thus giving the Covenant only to Isaac.
All of Keturah's children were sent off as mamzers, away from Isaac.
Judah sinned by marrying a Canaanite woman as well. His goy wife is the one who told her son's Er and Onan not to give their seed to Tamar. She also refused to allow Selah to marry Tamar.
It was until Judah's evil goy wife died that Tamar was able to take up her rights to a levirate marriage.
Joseph married while exiled from his kin. It doesn't say his actions in marrying her were righteous either. There is a difference between
prescriptive and
descriptive. Moses as well, who also "had sent away his wife Tzipporah and her two sons".
Solomon sinned by marrying Goy women: "Isn't it because of these things that Solomon sinned?" (Neh. 13:26). He lost the eternal throne because he violated Deut. 7:3.
"They have taken some of the women from these nations as wives for themselves and their sons, so that the holy seed has assimilated to the peoples of the lands... When I heard this, I tore my robe and tunic, pulled hair from my head and beard, and sat down in shock." (Ezra 9:2-3)
"You have acted treacherously by marrying goyim women and have thus increased Isra’el’s guilt. Now, therefore, make confession to Adonai, the elohim of your ancestors; and do what will please him
by separating yourselves from the peoples of the land and from the goyim women." (Ezra 9:10+)
"We will live by Elohim's Torah, given by Moshe the servant of Elohim, and will perform and obey all the mitzvot, rulings and laws of Adonai our Lord.
31 (30) “
We will not give our daughters as wives to the peoples of the land or take their daughters as wives for our sons." (Neh. 10:30+)