Before we start pointing fingers or throwing mud, was this bug fix which 
apparently breaking setuptools introduced knowing that this would break 
setuptools users?

I'm surprised that nobody at all tried to use the release candidate with 
any of the listed packages.

Given the number of packages that use setuptools and have been widely 
distributed, I expect that even if a fixed version of setuptools was 
released tomorrow, the damage would already be done, and most people 
would just have to avoid 2.6.3.

How hard would it be to release a 2.6.4 which differs from 2.6.3 only by 
not breaking existing setuptools distros?