Being a parent is not on the same level of surgery, lets be real here. Whenever it becomes required to get a Masters or PHD to even be a parent then i might defer to this line of thought.
I don’t have kids but i bet you i have a pretty good idea what a given parent is doing right or wrong. Offering unsolicited advice to a parent that’s struggling or being nasty to them is an issue unto itself that has nothing to do with me or someone else having kids or not. Again by your own line of thought, if i did have kids then i am 100% ok to be an asshole to the parent in this instance because having a kid gives me that right? Gotcha.
Again i disagree. Being a parent is difficult, but that doesn’t mean that outside looking in the whole parenting thing is a mystery that can only be deciphered by other parents.