I think it's important to note that it's actually the developer that assigns the age rating to an app and not Apple. Of course, Apple can refuse to approve an app if it decides that the rating is inappropriate but the original article does not state that.
Apple doesn't reject apps because they're stupid, they reject them if they fail to comply with the terms stated in the developer program agreement.
The real problem here is not that they reject apps that fail to comply with the dev program agreement -- that should be expected. The problem is that Apple keep creating new, arbitrary and undocumented reasons to reject both new apps and updates. Where, for example, did this "any apps with a UIWebView have to be rated 17+" come from? Has anyone seen a policy from Apple?
Can't you just post a link to a bug tracker in your product description?
You can but many people won't use it.
In the description for my app I have a link to the website (which has a support email address) and my support site (UserVoice). In my app there's an "Email me" button, a link to the website and the support website, yet I still get bug reports and feature requests posted as reviews.