I think a lot of the non-professionals start with parsing and do not get exposed to backend. I have read two books about interpreters/compilers and they don't touch the backend very much.

Maybe this is introductory for backend?

That's part of it. I think another part is that it seems like the students are asked to read the papers behind a lot of the concepts, and academic literature is not generally very accessible to undergrads. (Not that they can't read it, but without someone guiding you through at least the first few papers, it can be a frustrating experience for many.)