It might be that they made the app fail if any of their outbound connections fail. This is very reasonable, as ideally the only calls the app should be making are the ones it needs to make to facilitate this functionality. So if connections fail, the functionality of the app can massively bork, potentially resulting in poorer customer service than if they simply showed a failure screen.
What's less reasonable is why graph.facebook.com is one of them. Why on earth would they be sending the most sensitive data of their clients to the least trustworthy of corporations?