GP is saying that since there is no license, the code is copyrighted and there is no allowable use anyone could put it to. Therefore, since you own the copyright, and did not license the code to a third party, you could have the app using your code taken down from the App Store.

In contrast, if you had put an open source license on it, then anyone would be well within their rights (assuming the license allows it) to compile and release a version to whatever app store they want.