bash tab completion
the details of programming languages
formatting source code
configuring window managers
What he's saying is, "Where are better abstraction mechanisms?" And that's a tremendously important question (whether you get it or not).
Should no programmers have to know about inter-process communication? Is dbus a bad IPC mechanism? Is IPC itself a flawed concept?
Those are interesting questions, because we can ask why and look for alternatives. Ryan's post and your response, not as interesting.
DBus as an implementation of messaging largely sucks. It uses an ad hoc protocol, there's little security, the C library implementation of it is a big mess, the socket interferes with remote X, introspection doesn't really work, and it uses far too much XML.
There are better abstraction mechanisms.