No idea.
But now it would be a good time for remaining CMs, particularly those higher up in the food chain (like Jon Ericson or Tim Post) to post a few words beyond the sad excuse for corporate boilerplate Juan M. was "able to share".
Even if, as has become standard these days around here, we can't ever read the whole story because of "reasons", at least a passable effort should be made to communicate when momentous events like these happens.
These were extremely highly-regarded community stewards, almost universally well regarded. They were particularly influential in how the product and community was shaped as it grew.
They can't—or at least should not—be dismissed silently.
These shadows can only be dispelled by being open and shedding light into the situation. If there is any light to be shed, which some doubt.
We used to have a "default public" philosophy around here. It's a bit sad how far have things fallen.
In case this reads like an accusation of sorts aimed at Tim and/or Jon... it is not.
It's just that I believe they would be the appropriate people to communicate with the community under the circumstances.
I have no way to know if they are choosing not to speak or are being told not to do so (because of the aforementioned lack of transparency), but I'm taking their silence —coupled with their track record— as confirmation that if they are not saying anything, is because they have been told not to.
It looks like we won't be hearing from Jon in any case, since he's moved on to greener pastures. (MoreHis decision was made months ago. More info here).