It's probably more like: Apps that look like standard Mac applications & behave like standard Mac applications will be accepted. All others will be rejected.

So Qt applications will be permitted as long as your careful, but they really want you to create native applications using Cocoa so they can ensure to keep control of the look and feel of applications for their platform (eg. if too many people switch to Qt, people ignore the Apple API and Apple lose control of their own platform, so they keep it on a tight leash)