Non-parents interfering with parenting style/caregiving style

Who hates it when a single, unmarried individual with no children tells you how to take care of baby/how to parent baby?🙋‍♀️Not wanting to sound obnoxious but I wonder why they think they can give advice? They are not even parents and do not have experience parenting. I am referring to people we interact on day-to-day basis and not professionals.