Apple has a history of yanking apps from the App Store that it discovers violates its policies in any way. If you managed to download it, you can keep it, but you won't be able to redownload it if you delete it. Until now.
With Apple's new iCloud service, you can easily see every app you've paid for in the App Store, even if you've since deleted it from your phone. This makes it easy to redownload stuff you want to use again. Included in that list are banned apps, and they're still there and available to download if you initially downloaded it before they were yanked.
Of course, if you never grabbed these banned apps before they were pulled, you're still out of luck. Ah, well.