You cannot avoid this. Looking up the naming authority in the registry IS a protocol. Consider that we have to get this behavior deployed to clients. We have to educate clients about how to do this. The client might know how to ask a proxy to do it, but that is knowing how to do it too.
Proxies are one solution - one of several.
Many users will have trouble doing even that. Sure it would be better to have the new protocol already built into browsers, but how do we convince enough of the browser vendors to do that. We don't have to if we can rely on a generic proxy capability. A proxy can serve everyone in the world initially, until it melts down. If it melts down, then people are using it and will want to set up more proxies closer to home.