This is good in my opinion. The more the rejection, the more the developers will tend to flee away from arrogant Marketplaces like that of Apple's. It will also, in a way, probably force developers to try out other marketplaces like the Windows Phone Marketplace and the Google Play store. Now, I do understand 500px is trying to create a uni-platform experience for its users, but now that 500px isn't allowed to publis…
Developers go where the users go (and pay). Until the Windows and Android stores start bringing devs the same type of money, it's still always worth it to "take the risk" of Apple's store. The only way I see this changing is if users themselves cared about an app being pulled, and this app doesn't seem big enough for people to care (maybe if Instagram was taken down).
[1] - http://www.entrelife.com/2013/01/case-study-of-android-vs-ip...