I find it fascinating that you don't seems to think your own advice applies to yourself. Shouldn't you
think and
ask before you decide that every negative response to this is baseless?
I would respectfully ask you to drop the word "offensive" from your vocabulary. There are people who get offended at things, but that is not about feminism, that is about feeling superior. And arguing with someone who is just trying to feel superior to you is pointless. Ignore them¹.
What we are concerned about here is not offense, but harm. I can see this event going one of two ways: 1) the women "win" and sexist men write it off as rigged/a fluke, or 2) the women lose and sexist men use it to justify their beliefs. There is a significant chance that this event could make women hackers' work harder. That's harm. I know a bunch of women hackers. Their work is already made unreasonably harder by sexism.
I think this world where there are so many barriers to people hacking is harmful. Like, there will be more good meals, and more happy time with family, and more love, and more cool shit, and more justice if we break down some of those barriers. "Offense" has nothing at all to do with it.
¹ I also respectfully ask you to look more closely when people seem "just offended" to you, and think and ask about whether they might be concerned about legitimate harm.