As a guy who attended an AdaCamp, which was a women-only main event with a small side event for guys, I say this is horseshit.
For the first time in my life, I was the visible minority at a tech event. And it was fucking intimidating. Even though everybody was perfectly nice and tried to be inclusive, I felt the odd person out.
But despite my personal discomfort, I could see how amazing this event was for the women involved. Suddenly they were in the majority. They felt safe: nobody was going to hit on them, stalk them, or stare awkwardly at their breasts. They were no longer women in tech, they were people in tech talking with other people in tech. From the Ada Initiative's reports and from talking with attendees later, it's clear the events make a huge difference.
After that experience, I am a huge supporter of events that are exclusively for minority groups. I think it's a great way to increase diversity in tech.
Oh, and as to your analogy to Jim Crow: you're trying to frame yourself as a virtuous anti-racist. But by trying to prevent minorities from meeting and organizing, you are replicating the behavior of the white people who helped build and maintain the Jim Crow regime. E.g., the slave patrols, a main job of which was keep blacks from revolting by breaking up meetings.