On a decentralized blockchain, you most certainly allow for posts urging folks to migrate somewhere else. Good ideas don't have to be enforced.
ETA: If you don't want people to leave, build a better blockchain. Newsflash: Centralized blockchain is not better. Tron is also not better.
Also,
"We'll allow the community to rule themselves as long as they rule in accordance with our wishes."
You can vote for any president you want as long as his name starts with Xi and ends with Jinping. Thank you very much for understanding.