No, he isn't. Another way that a UIWebView can provide a super experience to custom NSViews is if the UIWebViews implement more of Facebook's functionality than the custom views, or if the features the UIWebView expose match the ones users want better.
- Facebook fails to deliver features through the superior approach ...
- ... but does deliver them through a lesser approach ...
.. then the mechanism they use to deliver the features provides a better user experience, because it has the features, thus justifying the choice to deliver them in the through a subpar mechanism?
That's ... circular. Painfully so.
It would be better for the user experience if they delivered features with the highest level of quality they're capable of providing, and that's demonstrably not inside of a UIWebView.