At the University of South Carolina, the typical outfit includes a comfortable t-shirt, a pair of athletic shorts and tennis shoes. Some students dress more formally, but rarely is anyone seen in professional business clothes.
Many argue that students are more productive if they are dressed nicely for class, but comfortable clothes are more practical for this stage of life.
The weather is important for students deciding what to wear because many walk to class. It’s easy enough to sweat through a t-shirt on one of Columbia’s hot afternoons. Imagine wearing a button-up shirt and dress pants. The point of wearing professional clothes is to look presentable, but that is no longer an option after walking through the heat.
Another problem with professional clothing is the expense. Broke college students don't have extra money to spend on professional clothes. While having a business outfit for interviews is necessary, buying a whole closet full would be too costly. It’s easier to wear the casual clothes that are already in your closet.
Finally, students live a fast-paced life. Many are busy enough trying to fit class, outside organizations and studying into their schedule. Throwing on a t-shirt and shorts is the quickest and easiest option.
As long as students make it to class and engage in the discussion, the professor is not going to care what they wear. College is a transition period between teenage and adulthood, so it can be hard to define that is appropriate to wear. There are ways to be presentable without wearing professional clothes. For many, college is the last time there won’t be a certain dress standard to follow, so students should not feel the pressure to dress up for class when getting an education is more important.
See the other side of the argument here.