OK. I am going to throw this out there. I don’t know how much of a debate will develop, but here goes…
My sister in law is totally against the word “panties” as a term for women’s underwear. Apparently she is not alone:
A quick google search turned up other instances of “pantie” offense. Looks like the word “moist” takes some hits too.
Anyway, she feels that the word “panties” somehow does a disservice to women the world over.
I think she is crazy. What do you think?
I"m against all dirty words.
Like “areas” That’s dirty.
Or “urges”. I’m getting “urges” in my “areas”.
Tip o the hat to Four on the Floor
That blog post certainly is insane. It has absolutely nothing to do with the word panties. I can’t tell if she was just rambling or if it was supposed to be a coherent idea that, if effective, might lead the reader to believe panty is an offensive word. She insists the word bothered her as a child, relates a horrifying tale of abuse of authority that has utterly nothing to do with the word panties, then reiterates that she dislikes the word panties. I suspect she was just rambling.
Maybe the domain name had something to do with that notion?
I prefer to refer to them as “feminine undergarments”.
maybe this link is better.
http://mamamia.com.au/weblog/2007/07/what-is-it-abou.html
I know my sister in law was more offended on a “the word panties is sexist” level. Unfortunately, I don’t recall exactly, as we had been drinking before (and during) the conversation. 
Stuck in the '50s copper? The proper term is Fabric-Based-Feminine-Nether-Region-Wear-Americans
I prefer “gaunch” myself. Sometimes I’ll elaborate - “undergaunch.”
Do women from north of the border wear Fabric-Based-Feminine-Nether-Region-Wear-Canucks?
I generally only use the word “panties” to say “don’t get your panties in a twist”. So I suppose based on that usage, it is inappropriate/offensive maybe even sexist. But come on - don’t get your panties in a twist over something so small.
Does that mean that men can’t get their pants in a twist? I can assure you, from personal experience, that we can, and it’s probably more painful for us than it is for women.
I expect more mirth and buoyancy out of babble. That woman is a downer. 
It could just be context but some women are offended by “Are those the panties your mother laid out for you?”
Actually I do say that to men too. It comes across as more insulting that way since I am then implying that they are wearing women’s undergarments.
ETA: replying to Giles
OK, since we are in the 4th day of a Federal trial which will likely determine once and for all when appealed to SCOTUS about SSM, and yesterday’s testimony was ongoing historical discrimination against gays:
If you say that to men, in what way do you mean it to be insulting to imply that they
re wearing women’s panties?
If somehow you can persuade us you don’t mean it, but they take it that way, in what context do they take insult in your experience?
Example:
I say “don’t get your panties in a twist”
He says (generally angrily) “I don’t wear panties”
I say “whatever you are wearing, just relax”
I generally don’t ask further questions, since this person clearly lacks the requisite sense of humor to appreciate the joke.
Sometimes they get the joke and roll with it - and tell me about their lace panties, we all have a laugh and then move on to whatever got their panties in a twist in the first place.
I don’t find it offensive per se, just kind of goofy and vaguely child molestery. I can remember years ago a girlfriend and I completely mocking the word and anyone who would use it ,and now I have a boyfriend who uses the term exclusively. And he talks about panties A LOT 
I can’t really see how it’s anti feminist.
Knickers!
I’m female, and gloriously unoffended by that word usage.
How totally… odd.
I’m a middle aged woman, with a young daughter. I usually call them underwear, but for variation I’ll use panties. I can no more see this offensive as I would call the word ‘blouse’ offensive.
It’s an synonym for women’s underwear. What’s offensive about that?
I notice in none of the articles you link to did the women explain why they dislike the word. They just seem to have an ‘oogy’ reaction to it.
Very very odd.