Not true at all - you can modify the source code from open source apps, build, and install on your own device without asking permission from Apple or paying a fee for a developer license. The only control Apple has is over app distribution.
Distribution under the App Store's terms is a GPL violation itself.
> Because, counterexample, Telegram is licensed under GPL and is has not been actively banned from the app store.
As long as Telegram owns the IP for the app, or has contributors sign a CLA that allows for relicensing, nothing is stopping them from distributing the app under the GPL and distributing it under an App Store friendly license.
Taking GPL code that you do not own the IP of, or that you do not have a license to distribute under your own terms, and distributing it under the App Store terms is a violation of the GPL.
[1] https://www.zdnet.com/article/no-gpl-apps-for-apples-app-sto...
[2] https://www.fsf.org/news/2010-05-app-store-compliance
The GPL issues are more to do with GPL fans being overly pedantic about the license. The source code can be shared outside the app store, the only thing the app store build/signature is doing is baking in the app store wrappers which aren't adding extra functionality. By this logic, distributing a signed build of a GPL app would violate the license.
I believe GPL 2 might be ok.
You can also distribute your own GPL software on the app store, it you dual-license it.
But I believe distributing someone else's GPL 3 software is a problem, because as RMS said he realized he had to add freedom zero, the freedom to RUN the software.
Remember that Apple stops you from RUNNING software, then gives/sells you the permission.
In practice, this means you cannot actually put GPL applications on iOS unless you get a CLA from every developer on the project. This means a lot of perfectly good GPL-licensed applications will never actually get ported to iOS. You'll never see, say, Blender or Krita on iPad until and unless they CLA all their developers so that they can actually distribute the port legally.
If Blender Foundation or whoever runs Krita does have a CLA requirement for contributors, then consider that particular example corrected, but my point still stands: You should be able to distribute GPL software on the App Store and have the GPL terms supercede the App Store TOS.
Again, simply not true. If you obtain the source code, build, and run your own iOS apps on your own device you have no issues with GPL compliance. Honestly I'm disappointed that more open source projects don't go this route. Blender could easily provide an xcode project that anyone can build and run on their device outside the app store. They choose not to, but there's nothing stopping them.
Again, simply not true. You don't need a paid developer license for local installs, and this has been the case for a very long time.
Sideloading Blender misses the point. If you need to buy a real computer to compile Blender, then you already have a computer to just run Blender on directly. Furthermore, sideloading isn't exactly Apple-sanctioned. It's actually fairly cumbersome: you either need a Mac to run Xcode on, or you have to run a piece of third-party software that you put your iCloud password into, which then uses some Mail/iTunes plugins to forcibly resign and sync your IPA. Oh, and you need to redo that every seven days or the app breaks. Furthermore, Apple could break or prohibit sideloading at any moment and you would have no recourse.
If sideloading was a useful way to distribute software, Epic would be distributing a sideloadable EGS and Fortnite on iOS right now.