Should professors intervene if a student is wearing offensive clothing in their classroom?
I'm a bit disappointed at the number of comments from people who say they need to know what the exact statement on this particular T-shirt was so that they can judge whether it was truly misogynistic before answering the question. The question is clear: What is the appropriate response given that a student is ``wearing clothing that is likely to be offensive and hostile to other students''? Debating exactly what constitutes misogyny (or any other form of hate speech) is not the point here. Surely a question about whether a particular slogan is offensive would be too localised for academia.se, whereas the question of how the role of professor and/or TA affects how/whether one calls out offensive speech/behaviour/etc is excellent.

A couple of the other answers express surprise/concern at the OP's comment


  I don't feel comfortable (or safe, for that matter) as a woman
  confronting a male student about an item of clothing that is offensive
  to women.


Many of the comments on this page illustrate why it can be so hard to call out misogyny as a woman. Women who call out misogyny are regularly accused of being "too sensitive" and told to "lighten up". On this page we've seen people who think they'd be a better judge of whether something is offensive than the person who actually experienced it, suggesting it may have been all in her head, refusing to trust her judgement, and claiming that no young people are misogynists. All this just from outlining a story that inspired a general question about calling out offensive behaviour. Is it any wonder that women may find it difficult to confront the person who's actually wearing the offensive T-shirt?

Finally, to actually answer the question:

Most universities should have something like a code of conduct which forbids discriminatory harassment. The one quoted in the question certainly seems to apply to a T-shirt with an offensive slogan. In this case the professor (or any student in the class) would be within their rights to object to the T-shirt. I might say something like "that T-shirt seems to be in violation of the code of conduct; please don't wear it to this class again", ideally in much the same tone as I would say "If I don't have your homework by tomorrow you will get a zero", but I'd say it loudly enough that anyone paying attention could hear. As with any instance of calling out something offensive, I would only do this if I felt safe enough: you should try to create a safe environment in your classroom, but not at the expense of your own safety.

If you don't feel safe or comfortable enough to call out your student (and I can see this happening especially if that student is also your peer), there might be other people you can talk to, for example the professor of the class you're TAing, or the head of the graduate program in your department, or the student's advisor. This might also be helpful if the student does not respond well when you first address them.