Why would the news say that app store is full of porn when you search it on Tumblr but not when you search it on Reddit? If they let at least one company do it it does seem kind of dumb.
Obviously you can still find nsfw content on reddit that isn't labeled as such, so beyond that, it's probably up to the developer's soft skills. reddit probably has some people who are good at framing the app in communication with review, escalating review decisions, and communicating content policies in a way that makes them seem consistent and trustworthy.
I don't know about tumblr, but unfortunately, I don't think many indie apps with user-generated content would have the bandwidth to develop the same relationship with app stores. So there is some de facto gatekeeping happening that benefits the largest and most well-spoken social networks.
by influence you mean "conform"?
The problem, as I said earlier, is that indies have no chance of spending enough time developing their app and also having time to do this or of hiring someone to do this. This is where the gatekeeping comes from. I think it actually keeps them from launching and growing, not just publish with neutered content (what you call conforming.)
This is an Apple rule. From the App Store Review Guidelines:
> If your app includes user-generated content from a web-based service, it may display incidental mature “NSFW” content, provided that the content is hidden by default and only displayed when the user turns it on via your website.
— https://developer.apple.com/app-store/review/guidelines/#use...