He’s the carnival brand ambassador. They simply cannot say “if you didn’t know, 99% of the things you gift them go into the incinerator, so give them cash” it would heartbreak many. One of the worst feelings is trying to be helpful yet cause more harm than good. This would include giving someone a gift than only to overhear that person immediately threw out your gift
I do fully understand your viewpoint based on the article but think corporate is saying this to not bring negative vibes to the passengers. If they banned all gifts there would be a flood of angry customers
To put it another way, if one were approach a crew member, hold a hat and a $10 bill in one hand and just a $20 in the other, tell them to pick only one, which do you think they would take (rhetorical)?