I don't think that's what they're saying, it looks more to me that they only care about employees being public about it, it's unrealistic to think that Sony could stop all their thousands of employees from talking about it in the work space, I bet even today there's Sony employees talking about it at work. If it was only about that then they wouldn't have banned employees from simply tweeting about the Sony donation in their free time.
But once again, I also don't think we should always keep Politics out of the workspace when it affects the very employees in the workspace, the most important thing here, are the employees, they create the games that we love and banning abortion has much larger consequences on the employees than not banning abortion does.
Most polls I see in America are near 50/50 split on the issue but the worse that can happen to pro-life is they'd be upset for a little while, the worse that can happen to pro-choice is they're stuck with a baby for 9 months, the physical and emotional stress of that and what comes afterwards so it's clear which would hurt corporations more.
As I've said, I don't care if someone is pro-life but don't force it onto others, there's having an opinion but a lot of these "harmless opinions" are leading towards dangerous paths of taking away human rights.
I like our system, given the checks and balances. People can get what they want via voting. Even if I don't like the end result, I respect our system.