This is a blog post that points out that you can back up your keys in a Microsoft online account, among several other options. You've managed to condense it to "Bitlocker is a bad idea". Which leaves me to wonder whether you actually read the piece.
They store the keys of people who give them their keys.
Microsoft's code is the most heavily reverse engineered in the industry. It's 2014, not 1995; you can't summon a "closed source" boogieman to win arguments about what they do and don't do.
