I would say that this kind of mission statement can only work if done at the beginning, as reacting in response to the work environment described by their employees was doomed for failure.
I know many people like Brian Armstrong, and the investors. They are all cut from a similar cloth and they honestly have no clue how to react. They don't know how to get women on a panel, they don't know how to get qualified people of color in positions to change things. They are just told what they did wrong and just shut themselves off from it. The very people with power to change anything get marginalized themselves. And yes, some - not all - of them actually are not interested in inclusion or really are racist and sexist. But for the former, there is room to empathize with these kind of people to steer their energy in more productive ways.