What went wrong? There is an obvious, superficial answer in that Wikipedia empowers self-selecting cliques. Compare the coverage of female porn stars, where a page that went up first in 2004 has been edited over 3,000 times by more than a hundred volunteers determined to make it as copiously referenced as possible, with that of "Female writers" which has no quality control at all
So there are quite practical considerations underlying this which have little to do with social justice concerns. Greater diversity makes for better content in some areas. Hence the head scratching on the part of the Foundation about what it is that makes women stay away, and how to balance things out more.
Wikipedia is about providing correct information, which is unrelated to gender distribution.
The Wikimedia Foundation and numerous commentators in the press disagree. See for example this recent Guardian editorial, or recall last year's controversy about the categorisation of women novelists in Wikipedia. It does affect how information is presented, and what information is presented.
What happened, was instead of the general use of talks to resolve the issue, wikipedia germany said "screw this, lets create a new page lock that only we can edit, not just admins".
Not quite. It was the Wikimedia Foundation that created and implemented Superprotect, to prevent changes from volunteers admins of the German-language Wikipedia.
"You don't go out and kick a mad dog. If you have a mad dog with rabies, you take a gun and shoot him." -- Pat Robertson, TV Evangelist, about Muammar Kadhafy