Part of the argument is that this is sexist. Part is that it's unprofessional. If there were also male strippers the event would no longer be sexist, only unprofessional. Would it still deserve moral outrage? Would it still be counter-productive?
I'm just exploring permutations here. I think half-naked dancing girls would make it hard to get any hacking done. But that doesn't necessarily make it a bad event (aside from sexism). A bad event to hack at, maybe.