Or perhaps it's because the whole "relational" stuff hides the nasty parts of arranging, indexing and querying data from the programmer and creates a vicious cycle of dependence and incapability that makes the average programmer think anything an SQL query can do is at the same time "magic" (because no one knows how it's done) and "natural" (because everybody can do it since it's assumed everybody is using Postgres or MySQL).
You can see an example of that in any of the many discussions about what features the Nostr "query language" should support.