I am curious about that too, unless these designers aren't very good and are just trying to translate print media to the web without considering the ramifications of the platform (see: almost every iPad magazine). Flash isn't a terrible platform to develop for. The app itself (as in Flash CS5.app) is pretty horrid, but it's not that hard to write ActionScript in vim or TextMate.

What Flash does offend is my sense of design, specifically UX design. Standard platform widgets? Nope. Standard platform behavior? Nope. Stealing keyboard focus? Yep. Bad scrolling? Yep. Back button? Nope.