No, closed ones are a betrayal. If someone doesn't upgrade, you can easily exclude them from communication and even build such logic in the protocol itself. It will pressure them to be up to date. I don't see an issue here.
You can't do that if the ones that refuse to upgrade are some of the bigger providers on the network.
You can if you care about security. That's exactly how the very same Google Talk was cut off from the rest of the XMPP universe, even before they decided to shut it down (they refused to support server to server encryption).
Open federated protocols with no obligation for providers to upgrade as the security landscape changes are a betrayal of user security and privacy of the highest order.
HTTPS is only becoming reasonable because Google can use its monopoly power and forced upgrade mechanism to bully website owners into adopting better practices. If we had a fragmented ecosystem of many open source browsers with user-consent upgrades and similar market share like the open web people wanted, certificate transparency would remain academic.
Personally, I consider the median advocate of open federated protocols to be more culpable for the wholesale violation of user privacy than the median NSA staffer.