Because these are minors.
When the kids are adults out on their own then (and only then) the parents will have no say.
Up until the sixties most people were bright enough to understand this simple principal without needing someone to explain it to them.
As I recall the 60s was the start of the ‘new age’. O’ Leary was a doped up guru who led generations into the feely goody mood with the help of any hallucinating drugs/chemicals available. I had a very enlightening experience as a church ‘leader’ with a young pastor who took the view that God was presenting all these phenomena so that we could make more Godlike choices.