No, SCOTUS did not just allow Alabama to use an unconstitutional map. The map Alabama will use was a 2023 remedy to the 2022 map. The 2022 map was struck down by the three-judge court in Alabama (later affirmed by SCOTUS) for evidentiary, not Constitutional, reasons.
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Chief Justice Roberts (who wrote Allen v. Milligan) even said the 2022 map failed for evidentiary reasons (as I had been saying for years) during the 2nd round of oral arguments in Louisiana v. Callais.