@Rarebear Back when I was much younger we used to say, “ladies wear hose.” I don’t remember where you live, but up north in larger cities usually pantyhose were a part of professional and respectable dress. My MIL from Mexico City also would always wear hose when I met her 25 years ago, even when she went for a doctors appointment. A skirt suit and pantyhose and a heel. It was the fashion and I think it is a holdover from not having naked parts of you showing. When I moved to Florida, an obvious hot climate, it took me a long time to get used to wearing skirts without pantyhose. At work I still had to wear them, but out everywhere else almost nobody did, but I did for many many months. It’s a great business. Pantyhose snag and then you have to buy a new pair. It’s almost as good as selling razor replacements.
Places of work sometimes opt for the more conservative dress code so the person who has zero fashion sense and zero awareness of their body can’t screw it up. I think it was @jca who said one woman should have worn hose her legs were so bad, but didn’t, and no one told her. If it was the dress code the business would not be treating this woman differently by asking her to wear hose.
Usually dress code is in a larger company’s handbook to avoid employees from not having an appropriate fashion sense at work.
I disagree with @gailcalled about relying on solely looking around at other women, because sometimes specific managers don’t correct or send home people who are not dressing appropriately, but it is still a problem and the person is talked about and not going to get a promotion most likely. In a small office it can be ok, but in a large business it is a good idea to know the official rules and one day the OP and others who read this Q might need to know. My husband one time was sent home to change from his corporate job early in his career. He had on black jeans. They were dark black, in very good condition, and in the office khakis and polo shirts were fine, it was a fairly casual dress code, but you could not wear 5 pocket jean style pants. I know they have that rule to avoid someone coming in in faded blue, worn out, possibly a rip in them, jeans. My husband knows better than to show up with raggy trousers, but the rule is there to avoid the problem with those who don’t. In Bloomingdale’s when I worked there we certainly did send home employees with no hose or with open back shoes. I remember one time an employee was being sent home by a manager who was not her own manager and the young woman said her manager never sent her home for the same thing. Doesn’t matter, now she was being sent home, and her manager had been wrong to let it slide. But, Bloomingdale’s works directly with the public, they care about a certain image, and in the case of the shoes they care about safety at work. We literally climbed shelves sometimes, even though technically we were not supposed to. We were always on our feet and the shoes need to be stable and not allow our feet to easily slip out. Although, high heels were perfectly fine, which one could argue are a hazard also, but I agree a slip on shoe, even flat, is less reliable than even a high heel shoe at 3 inches.