Did Jabba the Congressman cite a particular article and section of the Constitution, or did he just pull this assertion out of his ample rear end?
A bill of attainder (also known as an act or writ of attainder) is an act of the legislature declaring a person or group of persons guilty of some crime and punishing them without benefit of a trial.
Deciding that someone you WERE giving money to is no longer going to get money is NOT declaring them guilty of a crime.
So while Nadler the Hutt DID cite a particular section of the Constitution, his opinion is worth what does come out of his ample rear.