From what I've read of this thread, this is highly relevant because a lot of people have a very shallow understanding of why this shirt is viewed as problematic. If you don't understand,
hopefully this will help you:
It doesn’t require any special sociological training to read the barely veiled message being communicated to these talented and ambitious women: You don’t belong here. We tend to think of this sort of outright sex discrimination as being a thing of the past in Western, industrialized nations. The Sexual Paradox author Susan Pinker, for instance, writes of barriers to women as having been “stripped away.” Her book is peopled with women who, when asked if they’ve ever experienced ill-treatment because of their sex, scratch their heads and search the memory banks in vain for some anecdote that will show how they have had to struggle against the odds stacked against women. As we’ll see in a later chapter, blatant, intentional discrimination against women is far from being something merely to be read about in history books. But here we’re going to look at the subtle, off-putting, you don’t belong messages that churn about in the privacy of one’s own mind.
[…]
What psychological processes lie behind this turning away from masculine interests? One possibility is that, as we learned in an earlier chapter, when stereotypes of women become salient, women tend to incorporate those stereotypical traits into their current self-perception. They may then find it harder to imagine themselves as, say, a mechanical engineer. The belief that one will be able to fit in, to belong, may be more important than we realize - and may help to explain why some traditionally male occupations have been more readily entered by women than others. After all, the stereotype of a vet is not the same as that of an orthopedic surgeon, or a computer scientist, and these are different again from the stereotype of a builder or a lawyer. These different stereotypes may be more or less easily reconciled with a female identity. What, for example, springs to mind when you think of a computer scientist? A man, of course, but not just any man. You’re probably thinking of the sort of man who would not be an asset at a tea party. The sort of man who leaves a trail of soft-drink cans, junk-food wrappers, and tech magazines behind him as he makes his way to the sofa to watch Star Trek for the hundredth time. The sort of man whose pale complexion hints alarmingly of vitamin D deficiency. The sort of man, in short, who is a geek.
Sapna Cheryan, a psychologist at Washington University, was interested in whether the geek image of computer science plays a role in putting off women. When she and her colleagues surveyed undergraduates about their interest in being a computer science major, they found, perhaps unsurprisingly given that computer science is male-dominated, that women were significantly less interested. Less obvious, however, was why they were less interested. Women felt that they were less similar to the typical computer science major. This influenced their sense that they belonged in computer science - again lower in women - and it was this lack of fit that drove their lack of interest in a computer science major.
However, and interest in Star Trek and an antisocial lifestyle may not, in fact, be unassailable correlates of talent in computer programming. Indeed, in its early days, computer programming was a job done principally by women and was regarded as an activity to which feminine talents were particularly well-suited. “Programming requires patience, persistence, and a capacity for detail and those are traits that many girls have” wrote one author of a career guide to computer programming in 1967. Women made many significant contributions to computer science development and, as one expert puts it, “[t]oday’s achievements in software are built on the shoulders of the first pioneering women programmers.” Cheryan suggests that “t was not until the 1980s that individual heroes in computer science, such as Bill Gates and Steve Jobs came to the scene, and the term ‘geek’ became associated with being technically minded. Movies such as Revenge of the Nerds and Real Genius, released during those years, crystallized the image of the ‘computer geek’ in the cultural consciousness.
If it is the geeky stereotype that is so off-putting to women, then a little repackaging of the field might be an effective way of drawing more women in. Cheryan and her colleagues tested this very idea. They recruited undergraduates to participate in “a study by the Career Development Center regarding interest in technical jobs and internships.” The students filled out a questionnaire about their interest in computer science in a small classroom within the William Gates building (which, as you will have guessed, houses the computer science department). The room, however, was set up in one of two ways for the unsuspecting participant. In one condition, the décor was what we might call geek chic: a Star Trek poster, geeky comics, video game boxes, junk food, electronic equipment, and technical books and magazines. The second arrangement was substantially less geeky: the poster was an art one, water bottles replaced the junk food, the magazines were general interest, and the computer books were aimed at a more general level. In the geeky room, men considered themselves significantly more interested in computer science than did women. But when the geek factor was removed from the surroundings, women showed equal interest to men. It seemed that a greater sense of belonging brought about this positive change. Simply by altering the décor, Cher-yan and colleagues were also able to increase women’s interest in, for example, joining a hypothetical Web-design company. The researchers note “the power of environments to signal to people whether or not they should enter a domain,” and suggest that changing the computer environment “can therefore inspire those who previously had little or not interest . . . to express a newfound interest in it."
That is the problem with that shirt: It sends the same sort of exclusionary message to women as the geeky décor does.