It's still off by default, especially on mobile.

And if you have a kid with unmonitored access to the internet, they're going to access nsfw content regardless of what a site operator does.

I think you may still have to flip a switch in settings saying you're OK with seeing that–but really you don't have to go very far to find content like that anyways, just click on the comments for any post and you'll find something questionable quite quickly.