Because I always say I prefer white grapes, but maybe it's like when Robert Winston gave a load of kids two identical servings of lemonade each, one poured from a blue bottle with robots and stuff on it and the other poured from a pink bottle with fairies and stuff on it, and all the boys said they preferred the blue one and all the girls said they preferred to pink one, except for one SUPER SMART boy who realised they were identical.