I had another comment refuting the GP (as you are), but the more I thought about it, I decided to delete the comment.
At the end of the day, you have to pay $99/year to publish on the Apple App Store, and on Android, although Google has had some shady practices around automatically flagging/removing apps from it's store, you have more options in terms of app distribution, such as F-Droid.
To my (now deleted) comment's point though, I don't see much of a relation between F-Droid and NewPipe, besides that F-Droid hosts it.
EDIT: other comment on this thread answers that last point I made and your question, and sums up what NewPipe has to do with the "openness" of the platforms [1]. However, I now wonder, what is stopping Google/YouTube from going after NewPipe & F-Droid?
Not just the money & the need to obtain another protform for app development (MacOS) but also the te inability to public GPL apps on app store (if you manage to get that far):
Correct me if I'm wrong, I'm not very familiar with iOS, but it's not so much F-Droid that makes Android great, but rather the fact that you are allowed to install apps outside of the Play Store. As far as I know, that's not possible on iOS without jailbreak (or the whole Testflight stuff that was being abused).
F-Droid is just a visible example of that functionality.
At the end of the day, you have to pay $99/year to publish on the Apple App Store, and on Android, although Google has had some shady practices around automatically flagging/removing apps from it's store, you have more options in terms of app distribution, such as F-Droid.
To my (now deleted) comment's point though, I don't see much of a relation between F-Droid and NewPipe, besides that F-Droid hosts it.
EDIT: other comment on this thread answers that last point I made and your question, and sums up what NewPipe has to do with the "openness" of the platforms [1]. However, I now wonder, what is stopping Google/YouTube from going after NewPipe & F-Droid?
1: https://news.ycombinator.com/item?id=23874943