They kept going because until Commonwealth vs Muniz is was legal to retroactively make someone regeister. What they claimed was everyone was still required to register under AWA. Now that Commeealth vs Muniz debunks that, everyone who was convicted before 12/20/2012 will have to be removed from the registry.
I have a feeling that the PSP will apply Commonwealth vs Muniz automatically but will refuse to automatically apply Commonwealth vs Neiman. So someone is going to have to sue on behalf of every SO who was convicted before 12/20/2012. They will lose but it will drag it out for several more months.