I think the point he's trying to make is that you can choose PHP and you're never going to hit a wall where it can no longer be used because the project is getting too big and serious.
That's a strawman argument to be sure, but I think it's reasonable to point out given the oft-repeated claimed that PHP is fine for small-scale hacking but is inadequate for "serious" software engineering.
Exactly... I hear so many people saying PHP is horrible for sites/apps that are big and serious, yet when I mention Facebook or Yahoo! Answers, they go quiet... What real time examples aren't good enough?
Way to many people jump on the "PHP is crap" bandwagon for no reason and they all repeat the same thing over and over.
Read the original post, he isn't saying that its crap with no reason, he is saying it is crap and giving a good 80 reasons that none of the alternatives have. And pointing to facebook just means it is possible to build something great with php, if you have hired the best developers in the world, and spent a ton of time writing your own toolchain. It does not mean that facebook could have done more in less time with a different platform. I have seen well written excel macros that did things I never would have thought possible, vba is still a terrible language despite that.
This doesn't follow at all.