Why is there a bunch of what looks like really old BASIC code at the bottom? Pretty sure most LISP processors will choke on that.

That's LOGO, not LISP.

The program at top is a LOGO interpreter, written in LISP.

Thanks, somehow I managed to grow up in the 80s without ever actually using Logo and getting LISP only in one programming course plus a little bit of Emacs (vi FTW!).

If you have to explain the joke, it's not a very good joke.