Facebook has already proven to be a huge antagonist in many many ways. We can, however, give Oculus the benefit of the doubt; they might have ended up doing nasty things even if they hadn't gotten acquired by Facebook, sure, but Carmack's past actions were never even close to the nastyness of Zuck's actions. It's just a matter of analyzing the past and making a hypothesis on the future based on that. I don't see what's so difficult to understand.