Send TSA a compliment regarding the supervisor. Describing what the supervisor did well, leaving out the "moron" comment (which was not appropriate for the supervisor to say to a third party), will likely generate more action than a complain about the line Officer.
I would separately send a note to the DHS Inspector General. Both CBP and TSA are DHS agencies and unless the GE card was mutilated or defaced, it ought to be acceptable. Make a point of noting that the card was in good condition (presume it was).