Earlier quoted context omitted.
Actually, if you'll read the ZNet article that post is based on you'll notice that users who didn't connect their Windows Phone calendars to their Google accounts before February are still screwed! See also http://windows.microsoft.com/en-US//windows-8/use-google-win... : I want to connect my Google account after January 30, 2013 Here's what you need to know: Unfortunately, with Google changing the way it supports EA…
Read the article again. Windows 8/RT isn't the same as Windows Phone (which Google confirmed in the article has been whitelisted). The source of that is the Windows team deciding not to add CardDav/CalDav support to the Metro-style Mail and Calendar apps, so you won't be able to use CardDav/CalDav from any other provider either.
CalDAV is the standard and it's pretty clear that Google is backing away from that along with ActiveSync for enterprises and therefore silo-ing Calendar.