I know some principled, driven, and wonderful people who work for Facebook.
While I despise Facebook as a company, that doesn't reflect negatively on said people, at least insofar as they do not work on the kinds of things that I dislike Facebook for.
I would however hold them to account and openly criticize them if they did start working on such things. And I can and do criticize them when they spin apologia for Facebook as a company.
Why do you draw that distinction? Do you believe it's possible to work for Facebook without at least indirectly benefiting the company as a whole?
No, probably not. But I still draw that distinction.
I'm not a strict consequentialist. I think that people's intents matter and that their inner lives have moral significance.
So, for me, that outcome (Facebook benefiting) is only one factor in the moral calculus. In the case of the people I know (and likely John Carmack, though I don't know him), it isn't the dominating factor.