even if it were stated in the license (which it wasn't last time i checked):

the license is the legal framework which is in place between the person who received the software and the one who distributes it. it describes rights and obligations for both of them. but it cannot possibly be legally binding between the distributor and somebody who did not receive the GPLed work. it's not the law. it's a treaty. it's valid and possible for the distributor to not give you the application at all, neither binary or source, because he doesn't like your face or your name. the GPL doesn't force anyone to give you anything. only after he gave you an application, and only if the application is GPLed, you have certain rights you may enforce in court if you want to. also, you can enforce those rights in case you *contributed* to stellarium under the terms of the GPL and now find the way the whole code is distributed breaks these terms.

for all others - those who didn't buy stellarium mobile and those who didn't contribute - the whole discussion is pointless. you can't be deprived of a right you haven't been granted in the first place.