This is making a common but wrong rhetorical move, which is ignoring the fact that qualified candidates of the preferred race, with the preferred genitalia or gender presentation, and with the preferred sexual proclivities just aren't out there.

It's not like there is a large pool of black developer talent that firms just keep missing. It doesn't exist. It could be created, but a separate and totally valid question is: why do that? Why should we want every group of people to be representative of the population down to the smallest scale in race x gender x sexual preference?