Earlier quoted context omitted.
This practice actually goes against the recommendation of iOS Human Interface Guidelines, although it doesn't seem like Apple actually enforces it: Display a launch image that closely resembles the first screen of the application. This practice decreases the perceived launch time of your application. Avoid displaying an About window or a splash screen. In general, try to avoid providing any type of startup experience…
That's a bit surprising to me. I haven't noticed this (not much of an app person), do many apps use the recommended technique? Personally I would find a splash screen that looks like the first screen to be confusing.
The app needs to load something close to 200 fonts (it's a design-oriented app). If they're not all present, the font choice list won't render properly. Lazy-loading isn't really an option -- otherwise the user will be sitting there watching the UI slooowwwlly render each font choice, one by one, while he waits to do something with them. Better to take the hit at startup, IMO, rather than making the user pause while he's in the middle of creating something.