Diversity is a problem in all of computing; to make it out that it is solely the problem of conference organizers is to miss the point and to over-concentrate the blame.
This was a few Rubyists trying to do something for their community - not interviewing for McKinsey.
Are you going to blame the technical community because 13 year old girls don't like it?
I think that's a false dichotomy. By doing nothing, we help foster the problem.
Personally I think quotas is one good way of helping solve the problem. The idea being that they counter the existing bias against some groups.
If there is no existing bias, quotas are indeed "unfair". If there are existing bias, quotas will be unfair to individuals. I still think quotas can do good overall.
If there is bias, and you cannot see it: you will perceive quotas to be unfair.
Even in my 7th grade programming course(back in the late 90s), there were 22 males and 1 female.
That did not come about without a lot of different people and organizations working actively towards changing the ideas of what and who kids would "allow" themselves to aspire to be.