The author mentions avoiding multiple logins and searching across forges. The former is already addressed by social logins / federated identity. The latter is not very useful today, on a centralized GitHub, aside from finding leaked credentials and vulnerable code.

Absolutely not. Social logins are unacceptable and I refuse to use sites that depend on them and do not provide a normal method to make an account.

Ideally projects like this can bring us a model where you don't need to login to some other forge to interact with a project but do it by forking it onto your own forge and submitting pull requests between forges.