I have one too (which I've since swapped for an email I actually use). I'm not one hundred percent sure, but I think it was the only option for a while (inherited from MobileMe, perhaps), or at least it wasn't clear that you could/should add another email.

Either way, Apple could definitely do something with regards to make it easier/more obvious to replace it with a useful email address, especially now as it becomes a federated identity provider.

I can't answer that. However, if you go to appleid.apple.com to create a new AppleID, you must use an existing email address.

When I create a new user account on the mac, it asks the new user if they want to create an AppleID. The default is to use their existing email address. You must specifically select an option to get an iCloud account. If you purchase an Apple device, you again have the option of an iCloud account or using your existing email address for your AppleID. Apple is not using some deceptive UI to get you to create an iCloud email address.

However, I guess you still feel it is somehow evil that Apple does allow you to get a free email account where the provider does NOT read your email content and use it to target ads at you. Suboptimal for Apple from a pure profit perspective.