In addition to sexism, the marketers seem to believe that "teetotalers don't really qualify as people in the same way drinkers do, and no I've never really thought very hard about it".
(They also seem to feel the same way about people who don't like massages, people who don't work out, and people who don't like cupcakes.)
There are no people alive today who were alive when cupcake haters were not eligible to vote in the USA.
Note that if the conclusion doesn't change upon the death of the last suffragist, the fact is irrelevant, and you bringing it up is a red herring.
The fact highlights how recent this level of discrimination is in our history, and why "being a woman" and "disliking cupcakes" are significantly different characteristics when you're discussing power dynamics and discrimination.
"The marketing material assumed that the people reading it would be heterosexual men...Assuming the whole world should revolve around what you find attractive..."
Spent about 5 minutes assuming that they were encouraging /women/ programmers to enjoy the female staff, and assuming all women in attendance were /lesbians/ ("Women: Need another beer?").
Like, "pff, not ALL women programmers are lesbians, you guys! ... ... ... oh wait. Oh ... "
To not recognize that the tech population is dominated by men is to put your head in the sand.
I like to code, I like to look at scantily clad women, and I fully believe they're just as equal as men.
EDIT: Downvote away. You don't have to believe in fact for it to exist.
To not recognize that advertising tech events that female programmers do not feel comfortable attending because they do not want to be treated like subservient beer-wenches is partially responsible for the continued decline of women in the tech industry is to put your head in the sand.
That's what people are taking issue with here. No one is putting you on trial for liking to look at scantily clad women. Trying to make yourself into some kind of martyr for "finding women attractive" movement misses the point so thoroughly as to defy belief.
In what other situations do you not feel that the minority do not have rights?
How does offering to have women bring you beer at an event take away your rights? Shall we be boycotting Oktoberfest next?
Some people might see it as a poor attempt at humor and not demeaning to women, but I'm sure others saw it as a reinforcement of their beliefs that women are for serving beer. When everyone laughs along, because they know nobody 'really means it' it sends these people the message that their views are OK and widely accepted.
If you don't think it's fair to compare racism and sexism, I suggest reading this Person Paper: http://www.cs.virginia.edu/~evans/cs655/readings/purity.html
Last I checked, women generally don't like being treated like perks.