Sometimes parents know their children, and what's best for them, better than faceless politicians (who we've seen are often attracted to said children for some reason).
Growing up in my household there was a time when I was allowed to read and watch whatever I found interesting. My younger brother was not. That was because my parents knew us and judged that at my level of maturity I was unlikely to be negatively impacted, whereas my brother would get nightmares or copy-cat things he saw that he definitely shouldn't.
That's how it should be. Yes, there are bad parents who will decide poorly. That's the cost of freedom.