I thought I ran the ftp.exe program from my PC, and thus the "ro" and "rw" commands would be from that executable.

Nope. Remember that you're not executing "ro" and "rw" commands. You're executing the LITERAL SITE command and telling it to send the strings "ro" or "rw" as its parameter. LITERAL SITE is the command to get the server to accept a command. In this case, the server is Hijack, so it's the one that executes the "ro" or "rw" command.