Because Diaspora is open-source, it attracts this sort of "look at how bad the code is" attention. I'm willing to bet that the first prototype of yahoo/google/facebook all had terrible code that may have lasted a long time. However, by not being open source, no one was able to critique them on their software design mistakes and instead had to focus on the product itself.

Since it is open source, Diaspora could probably use the writers of these critique pieces (bad design, security holes, etc.) to actually make a better product.

(Tangentially, why are there so many blog posts about Diaspora's code? Is the code actually unforkable? Or is it just because Diaspora painted itself into a corner promising a secure social network on a relatively quick timeframe and now everyone wants to prove them wrong?)