I don't think that they are like to do harm in moderation. It's not that that I object to, it's buying into the marketing that says it is acceptable to have children (young teens in my friend's case) dressed and ready at the door in time to get to the supermarket at 6.00am to buy a drink that has been made desirable by its manufactured scarcity.
Children have always liked sweet treats and I'm not po-faced about indulging them sometimes, but that seems to me a step too far. To me, the susceptibility to marketing is more dangerous than an occasional sugar hit.