1: whether or not the leak is selective, we don't know. Given it was a sealed doc in a lawsuit vault, it might not be that selective, and it very much looks like they may not even be the people who leaked it.
2: the morality of the app was never the topic.
3: Facebook has been doing switch & bait for too many years, even with one's own data. See https://ruben.verborgh.org/facebook/ for more details on this. It's the same story as Twitter: yes, come, develop apps, spread our influence, then board up all the resources. This needs to stop, both from an anti-trust perspective and with developer awareness.