Earlier quoted context omitted.
I'm confused by your question. A lot of organizations have similar concerns. Do you believe that all discussion of diversity is equally nonsensical, or is there something about Github's stance that strikes you as especially so?
I'm in an asian country where racist is (mostly) not a thing, so why people cares about those rates is a mystery for me. In my thought, if there are 2 candidates for a leader role, and they decided "oh, we need more women in leader rank, we should chose her", it is just wrong. Race/gender shouldn't be even considered as a factor in those situations.
If someone rolls a die 10.000 times, and 75% of the time it lands on a six, then instead of "not caring", many people will care. Particularly those that are not betting on the six. Though the people betting on the six have a vested stake in "not caring".
In other words, it's a matter of bias.
If talent is not correlated to race/sex, then we can expect that the number of people of various races/sexes that are represented in the industry should roughly match the general makeup of the population (ie it's a mostly random distribution). Instead we see that this is not case. So either, talent is correlated to race/sex or there is a bias somewhere in the process.