I don't see what that would really accomplish, though. All companies already publicly advertise the 'moral' beliefs you mentioned, yet continue hiring white male whiteboard challenge mavericks.
No, not all companies. Many still follow the age-old wisdom of staying out of the social commentary business. I think the goal of this endeavor is to change that by convincing the tech workers to create a culture of doing so where it didn't exist before.
The only age-old wisdom I remember from my great-grandfather is "never trust the British, and kill every French on sight".
Regarding this issue, I'll stop demanding that corporations act morally above and beyond what the law requires when they seize to influence those laws.
This feels like a very political move that has little to nothing to do with tech. If you build a union or trade organization which has influence over the biggest CEOs in the world, you have consolidated a lot of power.
I'm left scratching my head after reading this, and I feel like YC may have lost its way.