It's right here in the App Store guidelines: 5.2.3 Audio/Video Downloading: Apps should not facilitate illegal file sharing or include the ability to save, con

It's right here in the App Store guidelines: 5.2.3 Audio/Video Downloading: Apps should not facilitate illegal file sharing or include the ability to save, convert, or download media from third-party sources (e.g. Apple Music, YouTube, SoundCloud, Vimeo, etc.) without explicit authorization from those sources. Streaming of audio/video content may also violate Terms of Use, so be sure to check before your app accesses those services. Documentation must be provided upon request. https://developer.apple.com/app-store/review/guidelines/#intellectual-property https://developer.apple.com/app-store/review/guidelines/#int... As to the why, because Apple could be sued by third parties for allowing this behavior for apps that Apple has vetted.