One might similarly ask why, in the past, a minority female pilot has had to go to hiring conferences of organizations run predominantly by white males.
I would say, "because that's where the recruiters were."
SMe answer today. If I were in the market for a job and thought I'd get my dreamshot by going to the Society of Upper-Class Kelp-Eating Radicals conference, and i didn't mind sending my dollars to said organization, I would.
Of course, there are some organizations I wouldn't support due to their values and goals. One example: NAWVPLA (North American WSO-Viper Pilot Love Association).