It's pretty crazy to think about what Apple is capable of doing now. By banning an app, they can easily kill a small company, and now they've caused some huge internal headaches for Facebook. I know Facebook broke their rules and totally deserved it here, but it's interesting to think about the power Apple has obtained by tightly controlling their platform.
You do bring up an interesting point. Apple's (expected?) responsibility here is to protect their users from malicious apps on their devices. It does seem reasonable for me what they are doing, but of course if they were to lose sight of their users' best interests, then this could become problematic. However, I think for issues like that we need to just trust the market to correct for that. If Apple were to destroy user trust, then I would not doubt that people would flock to their competitors (Google, Samsung, etc).
