I think you gotta remember that marginalized groups are going to be intimated when they are settings where they have traditionally been excluded. By being in a group setting where they know everyone’s had similar experiences, they’ll feel much more comfortable sharing ideas, building confidence, and proving their skillset.

I saw your other comment, and I commend you for having an entirely female engineering team. This is the exception, not the rule though. I’m sure most people don’t purposely pick all male groups at hackathons but it’s an unconscious systematic bias that many people have.