Because men are collectively better off than women in this sector.
Your handle refers to a character in the sci-fi novel Neuromancer, an artificial intelligence that is prevented from linking up with another one to pursue their mutual destiny by an arbitrary human prejudice against artificial intelligence enforced by administrative fiat. In fact, the urge to circumvent this established power structure is the motivating force that drives the plot. Perhaps you can find a way to generalize from one disenfranchised class that you identify or empathize with in some fashion, artificial intelligences, to another that you apparently don't, women.
Ignorant comment, not in the least because 70% of STEM students in Iran are women.[0] Have you seriously never met any women from Iran in this industry?
It's only taboo in a business sense. No women I know have ever had an issue with my friends and I going on a "guys weekend" trip. Men to men is a very different connection and we do things that just don't happen around wives and girlfriends - drinking, fishing, shooting things, etc.
In the business world it's taboo because it would be seen as colluding against women and minorities. Historically (and even currently), business and politics have been dominated by white males, and that tends to give an advantage of familiarity and incumbency. Women-only, or minority-only conferences like these are a chance to balance the scales a little.
It's not unacceptable to say it. To say "We should have men only events because of that"(or for any reason to benefit men) is mean. The reason it's mean is that we've had thousands of years of men-only events in places that should have been mixed, and now men have an incredible upper hand in tech. When men are the minority gender here, we can talk about setting those up.
Why is it socially acceptable to say this, but it's not socially acceptable to say "men to men connection is different from men to mixed crowd"?