Why is NSFW content not allowed on this app?

Because the app was originally for children and the younger generations, and allowing it would just turn it into a porn site. It would lose 90% of its fanbase and popularity and would end up being some sort of onlyfans scrollable service.

??

Sorry to tell you but, I'm in all sorts of NSFW groups. Not sure what you mean.

Because there are slots of  minors using it, simple as that.