What is it with the ad-hominem attacks today? I am probably a sloppy thinker and possibly a very bad one, but luckily I've received some very good education, and in this particular case I didn't even need to think at all. I simply informed readers that by modern definitions of sexism, absence of women from places of influence
equals sexism (at least somewhere in society if not at a particular workplace). I am certainly not invested in this... oh, wait, actually, you're right, I am – I'm a feminist (or, at least, I'd like to be) and I want to live and work in a more egalitarian society. If you take any issue with this thinking, I'm kindly pointing you to the last 50 years of research in history, sociology and anthropology and the relevant researchers. Take it up with them (but don't tell them they're emotional as they'll take offense because, you know, they're emotional).
And, again, I'm sorry for my sloppy thinking, but I believe that "consider whether there is discrimination against Down Syndrome sufferers amongst tenured faculty on math departments" is not a counterexample because pertinent disability most certainly doesn't fall under any definition of sexism/racism and other unfair discrimination (same goes for quadriplegics in the NBA). Pitting disability against sexism as a counterexample appeared to me to be a brow-raising comparison. This fallacy is called reductio ad absurdum or a straw man.
If you'd like, I can come up with a better counterpoint (or so it would seem to my feeble mind, which I actually had to exercise for this): white players in the NBA. However, that, too, would not fall under the modern definition for racism, as racism (like sexism) is "prejudice + power", and I don't think anyone suggests white men lack power or influence in American sports.
And if I was sloppy by not qualifying the term "a well defined group of people" to exclude disability, forgive me, I thought it was patently clear from the context, namely a discussion on women. And please don't try to counter with discrimination against those who don't know programming or village idiots, because the definition excludes that kind of "discrimination", too, and I hope that's clear enough without me quoting vast amounts of research verbatim.