On a moral level, I do agree with keeping children from accessing certain content online, especially porn. I think I’d be happier if I porn was less accessible to me until I had the mental faculties to understand it.
On a practical / policy level, I disagree since there is no way to stop children from accessing this content without drastically hampering the freedoms of all people. I see no good solutions. I really feel bad for parents who have to raise kids in the internet age.