> If it's informational then that doesn't sound like something that needs an age check.

That is actually the main problem with all that. Because, as far as I know, some informational websites and forums were legally challenged (sorry if I'm expressing this in a wrong way) because they were hosting content "related to self-harm". Does informational content encourage self-harm behaviours, is it dangerous and should it be brought down? Well, I'm not a doctor and I can't really say, but... I hope you get my point.

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> And a site encouraging depression, if that actually exists and works?

There's a lot of such websites. They're called "news websites" (joke intended)