"Everyone" includes everyone from grandmothers trying to master software that will display pictures of their grandkids to graduate students struggling with compiler error messages in a new language.
No one reads manuals, hardly anyone reads on line help - and those who do often don't get the help they need.
Here is the course description from the web page maintained by the Department:
An introduction to user interface design, which encompasses design of the user interface and the functional design of the whole system. Students will read and critique papers and articles, evaluate and critique existing user interfaces and design interfaces of their own. Working in small groups, students will use either interface prototyping tools or conventional rapid prototyping systems to construct an experimental interface.