I'm half convinced that the actions that WordPress have taken are in violation of the GPLv2 which the WordPress source is licensed under.
Discussion
While it's definitely sleezy to use your control of the underlying repository I don't see how it violates GPL?
The GPL requires the the source be made available. Blocking WPE from accessing the public source could be perceived as violating that portion of the GPL. I'm not a lawyer so I could easily be wrong.