Very interesting read. Their criticism of the framework seems pretty valid. I’ve seen newer users be confused, how can they read Mastodon from Lemmy? Not as easily as reading Mastodon from Mastodon.
Usually it’s enough to explain that every application really is it’s own thing. If they are closely related enough and chose to use features in the same way, and more or less they are different applications for a similar purpose like Mastodon and Calckey, they will probably work well together. The more their functionality differs the more their interoperability will vary. Even Lemmy and Kbin had upvotes that were not interoperable until a few weeks ago, and federating Mastodon and Bookwyrm gets me status updates but that is not the real utility of Bookwyrm imo.
Diaspora could be made to work but they are right that every new federated product will work in unpredictable ways and can be confusing to users.