Goodwill is just being like any other company and sticking to policy. If they kept tabs on everything that people were looking for and wrote them on post-it notes, their monitors would be palstered in notes, quite a few people might not return after being set aside and you run into people trying to fight for the same stuff.
Value Village tried this briefly and their stores started piling up with on-hold junk.
It wastes their time and storage space which costs them money. It's much easier for them to be black and white on the situation, even if we don't like it.