Thanks for reaching out here in Community.
As mentioned by @renojim, are you accessing the channel through The Roku Channel? Parental Controls settings do not apply to channels outside of The Roku Channel (such as individual channels like Netflix or Hulu), and they do not prevent users from accessing content elsewhere (such a provider's website or mobile app).
You can modify or set Parental Controls for The Roku Channel. Once you access your PIN preferences, follow the steps to set a parental controls PIN. To learn more, go to How to set Parental Controls for The Roku Channel.
See related article:
How to block content using parental control
I hope this helps. Let us know if you need additional support and we will assist you further.