It's not the same as an online store. There is a way for people to know kids are in a place they shouldn't be or to deny them access to adult content in real life. In Steam, there isn't
Adult content on steam is marked as such very clearly.
Under Community Content Preferences, you'll see an option for Mature Content and Adult-Only Sexual Content.
You'll also be preventing from accessing mature content depending on the filters in your account settings, and in the Family Management section of steam, for Family Shared Libraries.
It's not clear to me what kind of age controls Steam has, but I suspect that they require certain forms of payment before accessing the "super adult" portion.
(For instance you cannot see the "super adult" store pages at all if you are not logged in.)
So what? A kid can still go get adult content without anyone else knowing or seeing. Most parents aren't able to set the family settings on Steam or even know their kid knows what Steam is.
Yes that's my point. The Internet does not have the kind of separation or age-checking that real life has, and maybe that hasn't been good for kids or adults
