It is, and I think an important feature. You can still earn steem coins and PAL tokens. People confuse what is decentralized and what is not. The block chain steem is decentralized, not the tribes, they are like private little islands sprinkled through out the steem block chain. Make to much of a ruckus, harass to many island dwellers, and it back in the ocean for you; to swim with, or be eaten by, the other sharks.