I didn't name it "proof of brain" and the person who did is long gone, after doing a lot of damage before he left.
It's a nice idea, but the reality is that it is a stake-powered reward system. Stakeholders pay the rewards (through inflation), and if you want rewards you need to post things that a consensus of stakeholders (not just individual ones) want to reward.
It's not perfect, but it's what we have, and, perhaps with tweaks but certainly not KYC, is about the best you can do at the base level with a native permissionless blockchain platform.
Second layer tribes, etc. can do things a different way if they like, so there are other ways to socially earn rewards.
RE: After dedicating 5.5 years to Hive/Steem, I've been informed by KING ACIDYO that I added no value