Well, at least there are some parents with a little common sense. Now days, kids young as 8 talk about having boyfriends and girlfriends with full consent of the parents and they don't see absolutely wrong with it.
Potentially homosexual or asexual or other differently identified children seems would seem to throw a pretty significant wrench in this, as well as potentially cause them a lot of unnecessary stress and anxiety and confusion, being blatantly confronted with an issue they might otherwise slowly come to terms with. I think this is a bad idea unless the organizers and cognizant of and make adjustments for such things.
Asexual and homosexual children? I don't think it is even an issue I think the problem is that the school have done this for a number of years and find it cute. I think is a little disturbing.