It's "not a big deal" that you were warned about what professor to avoid basically as soon as you got to school.
It's "not a big deal" that that same professor was untouchable by the administration because he was too famous.
It's "not a big deal" when going to parties at a conference comes with warnings of which of your fellow scientists are dangerous.
This is very real.
I remember these things so well from my grad school days. Being told to be careful around a certain department member who was known for seducing grad students and who had received a really minor penalty from the department when it was discovered (yet, ironically, another professor who did the same thing was suggested as a committee member to me and he was never outed or punished at all). I also remember being warned at meetings who to not be alone with because he was known for being "handsy," and about one scientist who had allegedly "taken advantage" of a woman who was drunk (no one called it rape).
The whole broken stair thing.
Then there were the amused warnings about certain "older gentlemen" who would possibly be hostile or rude to us female grad students because they "didn't think girls should be doctoral students."
Sexism is so cute, quirky, and eccentric when it's an old, famous guy practicing it.
And OMG, there was my friend who was actually fired by the person who was directing her thesis project because she refused to share a room with him at a conference they were attending. She got hired back by the department when she complained and ended up working in a different lab, but she lost her chance to finish her original project. What happened to the dude in question? Nothing, except maybe a talking to. And he wasn't even in a tenured position (he was a soft-money researcher), so that wasn't the excuse. The reason it was tolerated was because he brought money into the university.
A university where the regents were in a lather about condom machines in the dorm bathrooms because of the message it sent to the voters of the state re morality. Puke.
And not mentioned is the very real truth: the percentage of women getting doctorates in most STEM fields has increased markedly in recent decades, yet the percentage of tenure-track research and teaching positions at major universities and institutions is still lagging. Women are more likely to end up in soft money or adjunct positions, or to be underemployed as technicians, and are more likely to leave STEM professions entirely.
Compared to all this, a shirt is indeed a small deal. One drop in a much larger ocean of shit.