I'm not complaining. The app store has been very good to us... we have sold a lot of apps, and we'll continue to sell a lot of apps. I didn't offer any commentary on this, and I don't think it's "unfair." I am just warning anyone who submits an app - I posted the exact email that was sent to me, and nothing else.
But, this is not part of some checklist you have before submitting an app. You'd have to be an incredibly savvy and aware person to know this... after all, this is our third version of the app, and our app has always included Wikipedia content. Also, it's worth noting that MOST apps that include Wikipedia content are rated 4+, just like we were when we submitted. Have a look at the apps on the App Store if you don't believe me.
But once again, I'm not complaining. I'm just trying to help people (like you) avoid the same pitfall. We changed our rating, and we resubmitted.