The way we hear things is different, always, depending on who we are, and what our experiences are.
I never hear about a group of "males" standing around - I hear about a group of men.
But I do hear about groups of "females" as if they are a separate species. And that's what I've seen others complain about as well, that female/male as an adjective to describe a person's gender, like on our driver's license, is one thing. Maybe not a necessary thing, but an adjective, all the same, which describes a person. But as a noun, it doesn't mean human, it can apply to all species. Like we are more connected to female dogs or apes than to human men.
It's that same uneasiness I get when I hear people referred to as "illegals" - as a noun, as if that's THE thing that defines them.
The first line of the wikipedia entry, which I'm using because it denotes popular meaning in some ways more than a dictionary, is "Female is the sex of an organism, or a part of an organism, which produces ova (egg cells)." You see how that's a slightly dehumanizing way to refer to a
person?
Contrast that with: A woman is a female human.
This is from a book review on Amazon, which illustrates the point in some way - from a review of
Play or Be Played: What Every Female Should Know About Men, Dating, and Relationships ... "The author, clearly a player in his own right, objectifies women throughout the book - even on the cover (refering to women as "females" while referring to men as the obvious, "men")."
There's a longer discussion in the comments (to be read from bottom up) here:
http://grammar.quickanddirtytips.com/woman-versus-female.aspx#CommentsThis comment from that discussion was especially interesting: "I read through all of the commentary on this "Woman vs. Female" issue without seeing mention of my BIG problem. I'm not as concerned about "female" the adjective as I am about "female" the noun. I cringe when I hear "women" or "girls" referred to as "females," as in, "These females are crazy!" (Mark almost raised the issue and gave a good example in an earlier post: "I was talking to this female.") You noted that "male" and "female" are used in the sciences (or in agriculture) to refer to male or female animals. (The auctioneer at the state fair talks about the "female on the auction block.") Prior to the past 10 years or so, I didn't hear people refer to others as "a male" or "those females" unless it was in reference to the slave trade. Enslaved Africans (and later African Americans) were dehumanizingly referred to as "males" or "females" by inhuman types who treated treated them and traded them as they would animals."