The other reason I dislike this assumption is that it's frequently wrong. Judging by the rest of his blog, the author does grok SQL. I'm pretty sure the Python to SQL example is either hypothetical or describes the author when he first learned SQL well in the past.
I don't mean to pick on you. I just see this attitude repeatedly in software development, and it leads to unnecessarily difficult software.
I've forgotten most of this as I've gotten used to SQL, but you can use variables before you define them (except when you can't (damn you group by not handling my alias)). Like all of this makes sense to me now, but it was pretty painful when I started. I distinctly remember WTF-ing my way through my first weeks with SQL.
Rust gives me a similar feeling.