I'm not disputing the fact that misogyny was (and is) and big problem, that women's contributions were either disregarded or coopted by some guy and credit taken away from the actual contributor.

That happened. A lot.

But in the times before the written history books, we should be less concerned about the gender of an individual who we think used a thing in a new/innovative way for the time. I don't think that studies of bone carvings or other ancient artifacts, being referred to as an "achievement of man" should imply, or was ever meant to imply, that it was done by someone with a penis. In that context, in all cases, for all intents and purposes "man" should, and as far as I know, is, thought of as "human" or "mankind".

This isn't a debate about the sociopolitical unfairness towards women, it's a semantic argument about using the term "man" to refer to a human individual or someone who is a part of mankind. Bluntly, I took the statement in the OP as a tongue in cheek joke by the professor. They know that's not what it meant, and used the assumption that "man" = "mankind" as the juxtaposition to subvert expectations, to crack wise about it. The same way someone would say "you know what sucks about twenty six year olds? There's twenty of them" where the premise directs you to think of someone who is 26, and the punchline indicates that your assumption of it being a statement about people who are 26 years old, was wrong. That's what makes it funny. Granted, that's not very funny, but it's the structure of a very common type of joke.

That's what's in the OP.

Instead, here we are talking about women's suffrage for a field where they probably only remark about the gender of someone as a footnote.