I suspect this was one of their biggest/only assets. I wonder (purely from a thought experiment point of view) how the original spin-out could have gone if the project had kept the name in trust and granted a worldwide exclusive license for a period of X years, where X was longer than the initial investment term, with a renewal option.
On the other hand, given what's gone down between both sides lately, it seems the split is somewhat less than civil, and holding onto the name and killing off the "annoying project which resents and criticises the company" might be suitably vindictive and designed to cause inconvenience to the project.
What I don't get is why they won't just give up the CM name/domain? Are they pulling an OpenOffice?