Yes, they are[1]. The GPL is incompatible with the App Store terms and if Apple is aware that an app uses GPL software, they will reject or remove it from the App Store.
That link is from 2011, and the referenced verbiage is nowhere to be found in the App Store terms. I believe that the current terms leave the App Store open to GPL software. Also, Apple will only remove software if you notify them of copyright infringement; it's not their job to preemptively perform licensing enforcement.
> Also, Apple will only remove software if you notify them of copyright infringement; it's not their job to preemptively perform licensing enforcement.
Developers of GPL software have had different experiences with Apple than what you're asserting. There is a direct incentive for Apple to police licensing incompatibilities if they are profiting from illegal distribution of GPL software on their platform.
I tend to think of this as reaction to GPL FUD; I know some people who have these so they never have to actually figure out the answer to this question.
