Why would they not? we all have to use computers. Secretaries used to be able to code, such a thing is not possible nowadays as programmers create more and more obscurity.
Corporate jargon is how companies hide away inefficiencies and illegalities. Now, jargon is usually not that, but most of the time it is. The same way programmers said a kilobyte is 1024 bytes (seriously?)
To add to your point, yes, do ask a random person what notepad.exe doe vs what vi or emacs does.
A text editor is user-facing; the underlying filesystem hierarchy mostly isn't. I'll grant some of it is; it would make sense for a user to know (and perhaps even care) about /home, and in a system that isn't centered around a package manager I could even see them caring about whatever the directory is for applications, but beyond that it doesn't matter how /usr is laid out, or how the CPU is microcoded, or whether the kernel is monolithic, or whether their applications are written in Rust or C#. It's a black box, and for less-technical users that's fine. I won't say there aren't ways to improve, even to simplify things, and I do wish that normal people still programmed, but the reality is that computers really are just that complicated, and once we get over trying to explain technical things to less-technical people, the FHS is fine for what it is.
"dev" is obviously for developers. "run" is where the apps are located. "bin" is the recycle bin.