This is a red herring. The problem isn't whether some group or another feels unwelcome (though we have empirical evidence some groups feel less welcome than others). Rather, the problem is various aspects of the sites make people who already feel marginalized feel even more marginalized. That's what we gotta fix.
Personally, I've worked with fine programmers who aren't interested in participating on Stack Overflow because they are afraid of the site. Each of them would raise the average quality of questions if they were willing to ask, so it's a shame we actively discourage them. If the thing that finally gets us to work on this problem is the experience of a specific group, that's fine by me. As long as we finally get around to doing what's needed doing for years.
And if we can make a dent on Stack Overflow, that work will pay dividends on other sites too.