I see it a little differently, I wouldn't feel good about keeping people around doing nothing of worth for the company. I guess they could have thought of other projects for them but that could put stress on other parts of the company. At least some of these people can now work for companies that do need them.
It might be because I never want to work for a company that thinks of me as dead weight. It wouldn't be a good environment to work in.
In this case the shareholders outside the multi-layered conglomerate are fairly distant, so I'd guess internal bean-counting is a more proximal pressure on Blizzard. They're owned by a holding company, Activision Blizzard, which is public, but has the majority of its shares owned by yet another holding company, Vivendi SA. So Vivendi's shareholders are the main ultimate shareholders, but those individuals control Blizzard in only a very convoluted and indirect way.
I would guess that you might see different kinds of decisions from an independent Blizzard, even if it were public (though it would also have more risks in that case).
It might be because I never want to work for a company that thinks of me as dead weight. It wouldn't be a good environment to work in.