Every legal expert has agreed on that at least,it was not a bill of Attainder.
I never said it was, although I suspect that if bills of attainder were not prohibited, there would have been one in this case. I included Madison's comments on legislative interferences in judicial affairs because the Congress's intent was to use legislation to affect the outcome of a specific court decision. That's a bad law, per the wise words of one of the most pre-eminent of the Founding Fathers.