Why does Google have bad HTML?

Look at their source code and try a W3C Validation...

[Daemon]

I just have an open speculation here... just wondering WHY does Google have so bad HTML?

Shouldn't they be an example of simplicity and correct coding? They don't even declare a DocType!

Or are they just coding as they are to save up bandwidth on every single character?

(not sure if this is the right forum, feel free to move this thread)