Earlier quoted context omitted.
Why it is important to know the difference between statically and dynamically typed languages? If one writes in only one of those (or one set) it is not important to him/her and doesn't specifically make him/her a worse programmer in that particular language.
If they didn't know it, I'd want to dig down into whether the understand the specifics of their particular language at least. I actually just sat down in a meeting with a dozen programmers, some of them with decades of experience, and half of them didn't know what functional programming was.
Your example shows that not every programmer has to know that.