The researchers selected a small-scale application (about 4,500 lines of C# code) used by the academic staff at the University of Kelaniya for scheduling events and managing online documents for evaluation.
That's hilarious, I have web apps (I'm stuck with) having individual pages larger than that, including tons of other crap. Refactoring allows following the DRY principle and removing duplicated code. It allows moving SQL statements all the heck over the place into single places where they can easily be tested and updated when bugs are found.
They're basically working with a program that's not really that awful in the first place and making it a little bit nicer. How about starting with absolute junk and making it useable? Unmaintainable code is a consequence of technical debt, refactoring pays that debt down and keeps things manageable. Sure you may not need to refactor right now, but taking the time to do it once in a while keeps things from getting out of control.