I've seen this kind of sentence construction many times and it does not seem odd to me. “For I am a bear of very little brain, and long words bother me," is a famous example. Is it important to the sentence that Pooh is a bear? We already know he's a bear. In fact, I'll say that it actually presents the opposite implication from what you reached. I think Milne is making a joke here: we already assume that all bears have very little brains and so the statement is humorous. We expect a contrast and yet there is none. "She is a woman who changed her mind frequently" would imply that ordinarily women do not change their minds frequently, but this one did (unless you feel the same sort of joke is being made).
So, the OP's question is, why did the original author choose to state the gender of the COO? In my opinion, they simply did it to make the reader feel closer to the situation. Stephen King discusses this kind of thing at length in a couple of his treatises on writing. He says that you should avoid adjectives because they clutter up the writing and make it more complicated. If you have doors of many different material, you should change your story so that those doors no longer exist because specifying all the different kinds of doors just makes it confusing for your reader. However, it's a thing people who are not well practiced at writing do very frequently (which is why Stephen King discusses it at length ;-) ). I'm with the first responder in thinking that choice of mentioning the gender is not indicative of any subtext at all. It's just clumsy.