Just to be clear, you are aware that you can't access the NSFW section without an account that opted in to allowing it right?
I don't see any reason for a parent to allow their child to have an account.
Edited: accidentally put "with" the first time
Viewing post in Itch.io getting rid of NSFW games is amazing
You might want to sort your double negatives. I do not think you wrote what you wanted to write.
Itch does not have an adult section. And you can't opt out of adult content. You will see adult content, even if you opted out. The only (!) thing the adult content option in your setting does is this: if you hit the browse and search, those games will not appear as results.
But visit a regular game, go to the developers page, you will see the adult games that developer has published. Click on a direct link to a game also works, though there will be a warning page in front. And also, you will see adult content if you select the adult tag. The setting is ignored for that. And a year ago they even had the adult tag in the tag selection list for account that did have opted out, so you could accidentally click. That has happened and they eventually "fixed" that. But not by making the setting work, but by removing the tags from the sfw list.
Oh, and publish a horror game and think it is inappropriate for 13 year olds, and now your account is barred from opting out of adult content.
There is much to fix in how the adult setting works.
Thank you for pointing out my mistake.
I was not aware that the adult search option would still be there without the setting. I do know from experience that it isn't there if you aren't signed in though. That said, I don't think parents should be allowing their children to get accounts or even wander unsupervised if the parents don't trust the children to use their own judgement on what is an isn't allowed for them. The fact is uncurated indie games can have arguably worse things in them than nsfw content (such as outright propaganda). As such, I think publishing games, especially horror games, should really only be done by adults to begin with, so that issue with the adult setting is not something I'm concerned with.
This sounds more like an Itch.io issue and not a "NSFW Is on the platform" Issue.
It is not that hard to make the UI do what it's meant to do and restrict tags to certain accounts. If itch did their job right, this wouldn't be an issue to begin with and you could have the best of both worlds; having a SFW Marketplace and also restricting games to certain demographics so you don't run into the issues of Games being suggested to the users it shouldn't be marketed towards.