Earlier quoted context omitted.
So, the tech industry is dominated by men, and this announcement was intended for the tech industry, so it's fine by you that it was addressed exclusively to men? It's OK that any techy woman reading it might stay clear so that they are not mistaken for being a server and/or don't have to put up with sexism like this? In what other situations do you not feel that the minority do not have rights?
Yes, because you clearly have no rights if you're mistaken for an employee at an event. 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.