Earlier quoted context omitted.
Yea but that is opt-in not opt-out. For example there are botnets that use specific domains, they get disrupted until they spread again when a domain or IP is taken down. The longer a credential phish stays up the more people are affected by it as well. If there is no way to ensure by default a domain is inaccessible when revoked it isn't a workable system for commerical applications.
You can build decentralized domain name systems with revocation. Many of the people building such things wouldn't be big into adding deplatforming into the base layer, though. These projects are about a more free internet, not about a more easily controlled internet.
Everyone wants to start a protocol but no one wants to maintain the network. They want it to run itself. They don't want to separate centralization of authority from centralization of platform/network. The former lets you circumvent blocks if removed and the latter avoids registry's, payments, corporate run internet,etc... you can't have your cake and eat it too.