The policies he mentioned only even apply to people that are already in the treehouse, using that metaphor. He's saying we should stop pushing each other around up there and help other people climb up.

Edit: Positive discrimination in hiring policies doesn't do much to make tech more diverse, it can only shift the diversity within individual companies. Once someone is already a software engineer, they're almost certainly going to be hired somewhere if they're any good. Giving them preferential treatment does next to nothing for all of the members of their demographic group who aren't software engineers.