The major difference is that people can choose a different network if they are unhappy with the moderation from any specific network. A channel on youtube can'

The major difference is that people can choose a different network if they are unhappy with the moderation from any specific network. A channel on youtube can't just decide that they are unhappy with the moderation by youtube and replace them with an other moderation team. They can leave youtube, but then they also loose access to existing subscribers on the site. Youtube users can also not decided they are unhappy with the moderation of youtube and whitelist videos or channels that youtube have blocked. They can leave youtube, but then the channels also need to leave or the user will loose access to videos. The distinction between centralized power and decentralized power is how much power each actor has in the system. In a decentralized system the user control who they want to see, the content creator control who can access their content, and the network control what content the network will advertise to users. In a centralized system the network control everything, and neither the user or content creator can overrule the network.