...was disappointed

Every corporation has a responsibility to protect its employees. This is all about mitigating risk and lowering their liability. Removing the video had nothing to do with limiting the speech of Nick Gisburne.

You were doing fine until the last sentence, but that is just plain stupid. Of course it had to do with limiting Nick Gisburne's speech. Even if we stipulate your point about the company's responsibility to protect its employees, that means that the Islamists' violent intimidation worked--not implicitly or indirectly, but explicitly because the YouTube's reaction was directly based on the threat of violence.

Are people really not going to get it until Christians, Hindus and so on start murdering their critics and demanding that other critics not be allowed to speak publicly? Or will the rest of us be like Martin Niemoeller, without anyone left to speak up when it's our turn?