Yes, Yes I am.

Let's be more specific.

Child:  a minor under custodianship of another.

Supervision:  providing meaningful oversight.

No child would rightfully be raised without supervision - you don't let toddlers walk across the street, you don't let 6 year olds watch porn, and you don't let teens go to the local pub (okay, last one is location dependent).  Are you committing child-porn when you oversee your 2 year old dressing?  Are you censoring their ability to dress themselves by helping them choose (weather, etc) appropriate clothes?

Many things in life, while we are growing and becoming mature (a process lasting well into our mid-20s), require oversight.  Both for safely and utility.  We can pretend otherwise at our and the child's own peril.  Go ahead and let your child smoke cigs, watch porn and read reddit; it's your child - do as you feel best - I suspect my child will find yours to be .... socially repugnant.

The point is blanket statements like you made are corrosive to the understanding of the discussion.  Unfettered support of "the child" in all situations is counterproductive.

Don't get going on "Parents don't always know best" ... true, they don't - but as long as Society allows any person in any circumstance to _have_ a child without any sort of parenting training, oversight, counselling, then Society must allow that person the ability to _raise_ their child.  For better or ill.