Sure PHP has improved since that was written, but I'm pretty sure it was accurate when it was written. And I suspect that it was probably a contributing factor in some of PHP's improvements since then.
It was accurate when it was written, but within a couple of years of that it wasn't yet it was still constantly used. Thats where it became damaging, people not grasping how inaccurate it was yet still kept pushing it as a current understanding of the language.