Parenting is one of, if not THE most important things you can do on the planet. You’re literally making and raising people. The future depends on you not completely screwing up and putting yet another damaged person on the planet. So, yes, parent shaming is important.
There are no parenting classes people are required to take before breeding, so all we have is a society is to shame the insane parents. Everyone makes mistakes, but the really bad parents make them purposefully and actively. Call them out. Post their misdeeds online.
That’s where the “insane parents” reddit page comes in. Those of use who were raised by total lunatics can vent, shame, and expose our peers becoming parenting fails of their own.