I don't know that they are it is just that if mentioned in some places it is seen as quite early or not flexible but circumstances in other countries maybe different, in Southern Europe children often have siesta style naps until much older than UK because of heat people rest in afternoon and eat later at night, especially in holidays, it maybe that other countires don't have same bedtime routine so it's more like child is tired PJ's on go to sleep as showers are in the morning rather than baths at night etc