Actually that's the funny part, this "joke" was in no way belittling women, it's idolizing them. It was made at the expense of the stereotypical male geek to whom women are otherwise inaccessible. Somehow it was appropriated as being about the female attendees.
No. You are wrong. The original flyer was clearly offering a perk of women delivering beer. The perk is first named "Women:" and then described "Need another beer? Let one of our friendly (female) staff get that for you." That first word "women:" is not aimed at a female audience. It's aimed at a male audience. It's clumsily using stereotypes of programmers as mostly single males. That's pretty offensive in itself.
Sorry for replying three times but after talking about it with my wife for a couple of hours, we both agree...this is an absolute over-reaction and a projection of women's general frustration onto a non-issue.
I'll try to respond to some of your points in this one answer.
You're right, sex wasn't being offered. I was trying to show how specifically mentioning the sex of the servers, in a list of perks, was a shoddy move. It plays to traditional stereotypes of male programmers as lonely losers, and it puts women firmly in the role of subservient to men; not good enough to be there as participants. It's lazy and stupid. It's not as if "treat people with respect"; "don't discriminate against people based on their age, sex, sexual preference, race, or ability" are new concepts.
You mention a mixer, where men and women can meet. (We'll assume "people can meet" because we're not being hetero-normative.) With your mixer it's going to be a social function. Men turn up, women turn up, people meet and talk. There'll be other people working there. People serving the drinks, for example. So, you have one group (the people meeting each other, who are different sexes but on an equal footing) and the people serving (who are different sexes, and who are on an equal footing with their colleagues; subservient to the meeting group, but because they are employees and not because they are women.)
You can see that it's different for work or for professional situations. When you're working in an industry that's trying to attract a more diverse workforce you need to try harder not to exclude people.
You mention an event that excludes men. Ignoring the male children that will be helped by that function, you're right, it does seem aimed only at women. But no-one is saying that there are not enough men working in the fashion industry. And there are strong socio-economic factors that mean women with children are more likely to need help than men. (Although I do hope that group considers changing their mandate to include "men and children" too.)
You mention places like "Hooters". In my opinion these places are horrific. I'd feel very uncomfortable if I had a daughter and she worked somewhere like that. But, they are legal, and if people are able to make an informed choice to work there and people are happy to pay money to go there then who am I to judge them or stop them? These are specialised services; they are a niche. There's a big difference between Hooters (who aim at that market; they don't care if women are not customers) and a daily deal API firm who should be proud to be part of the modern inclusive world.
Finally, you say:
> this is an absolute over-reaction and a projection of women's general frustration onto a non-issue.
The over-reaction comes because some people just don't get it. It's the 21st century; suffragettes were campaigning for equality more than a hundred years ago. It's definitely an issue - the wording was clumsy and lazy and stupid. The fact that they got jumped on so hard is a good thing - it shows that people actually care about this stuff.
You mention women's general frustration. That's a really important point. Josie Long (she's an English comedian) says it well here. She talks about the general everyday grind of stuff that she has to put up with, just because she's a women, that her male colleagues don't.
 In theory you should have religion in there too.
 Dating sucks. It sucks for very different reasons for men and women. I understand men who are annoyed or angry or bitter or frustrated at their dating experiences, and I'd probably agree if they said that men and women are not on an equal footing when it comes to dating. I'm handwaving over it.
"... specifically mentioning the sex of the servers, in a list of perks, was a shoddy move."
I disagree. I don't see anything wrong with it for the same reason that there's nothing wrong with advertising that scantily clad women will be walking around at a comics convention.
" It plays to traditional stereotypes of male programmers as lonely losers, and it puts women firmly in the role of subservient to men..."
In your opinion... and you only have that opinion if you actively work to extrapolate that meaning from what was actually said.
"It's lazy and stupid. It's not as if "treat people with respect"; "don't discriminate against people based on their age, sex, sexual preference, race, or ability" are new concepts."
The problem is that in reality, there are differences between men and women, races/cultures and people with differing levels of ability. That you can't accept those differences and are offended by anyone else that addresses them is where the problem comes in.
That you think women are not being treated with respect here is a fault in your own understanding. There's simply nothing wrong with targeted advertising.
"She talks about the general everyday grind of stuff that she has to put up with, just because she's a women, that her male colleagues don't."
Right, but projecting those frustrations onto something completely harmless is still wrong.
Also, as if to put an exclamation point on this conversation... my company is moving it's office this week and guess who didn't have to do any of the work of moving or disassembling our furniture or other hardware?
I don't hear men complaining about always being targeted for this kind of work. I'm not complaining either, I just happened to remember our conversation as I was lugging our office stuff around. I really don't mind it when a woman says "Oh, I need a big strong guy like you to do X", even when the woman in question could probably handle it herself if she really tried.
Complaining about something like that would just be a waste of time and emotional energy, besides the fact that there's really no need to complain at all if you acknowledge that "equality" is a fiction.
The women themselves were not being offered. Serving of beer by women was being offered. The chance to meet a woman was being offered. Nobody was offering sex with a woman or any kind of woman sex slave.
If I advertise a mixer where men and women can meet each other, does anyone have a problem with that? I don't think so.
Should we all get mad at Hooters or Chipendales next?
(EDIT: Seriously, do you really think that men should be offended that Chipendales exists? Why?)
Also, I'd like to know... what's wrong with appealing to sexual desire?
The women were not being offered as chattel. There's nothing wrong with sex.
You really have to work to be offended by this one. Well, maybe you don't, but it certainly defies logic unless you read into it, which you are most certainly doing because the words themselves don't really back you up.