indeed, the #fediverse is more closed-world than open-world. you see this in the so-called "rejection" of json-ld among presumably the majority of fedi implementations. because for the most part, AS2 lets you ignore json-ld. it only matters for extensibility, and (specific criticisms of json-ld aside) json-ld also mostly allows you to ignore it.
so why do people still complain about it?
well, there is the concept of "context" in json-ld, which represents shared understanding.
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