"People will be able to opt-out of HTTPS for maximum speed if that’s how they roll." Why is that even an option? This entire article is written in such a way

"People will be able to opt-out of HTTPS for maximum speed if that’s how they roll." Why is that even an option? This entire article is written in such a way that most users are going to assume that Facebook is going to start loading at a snails pace. Turning on SSL is technically slower, but it certainly is not going to be noticeable. Perhaps if all Facebook was serving was a couple of small text files, the overhead associated with SSL could be noticed, but with that isn't the case.