It's not just designers
People in IT rarely seem to be interested in spending time watching what users actually do. Specs are often thrashed out with managers of the users who don't spend any time with them either. I've winced when seeing people in the call centre trapped between an angry caller (with broken $EXPENSIVE_THING) and shit software that doesn't tell them what they need to know.
The other thing with software for internal use: if users are on it all day, does it make more sense to have something that takes a little longer to learn but once learned is very fast to operate, or to have something "intuitive" that's always slow to operate?