I'm not buying that as an excuse for why the implementation REFUSES to let you on the WiFi.
Besides the fact that it's terribly fragile (as seen here), but if it's really an anti-imposter measure, it's a pretty awful one. (Okay, we'll just MITM every non-apple.com URL).
A great many wifi networks are open to the public, but redirect all HTTP requests to a login page. Think airports, coffee shops, hotels, etc. This is called a "captive" network. The apple.com request here is a heuristic to detect the "captive" network, so it can show a web browser inline that shows you the redirected URL so you can log in. This is actually a really nice feature when you're on a captive network.
Right, as I mention in another comment, I'm well aware of this. However, it shouldn't be the end all be all and it should be more redundant anyway. It should use more domains. It should still allow the user to use the Wifi network if they want to. etc.
Besides the fact that it's terribly fragile (as seen here), but if it's really an anti-imposter measure, it's a pretty awful one. (Okay, we'll just MITM every non-apple.com URL).