I'd guess that most parents agree that they don't want their kids drinking alcohol and don't want others selling it to the kids. That's why this behavior is made illegal.
However, I do not think that there would be such consensus on other questions, like when you should tell how babies are born, what politician is not doing a good job, or what books and TV shows should be banned for kids at home, etc. There is no agreement on these matters so there should be no laws governing them.
At least, I assume that the people you want to give the freedom to decide matters by themselves, are also people who would accept changing their mind (at a greater scale changing the consensus) when faced with credible facts going against their beliefs.
To take your “when you should tell how babies are born” example, I think we agree at some point kids need to know. There is no consensus on when it should happen exactly, but we know a portion of the kids will have life or death issues if it’s not done at puberty.
As I see it, idealy we’ll want to put laws to enforce sex education at puberty, and let parents do what they want before that.