The "relational" in relational databases is not about department number in employees referencing departments.

What the model calls relations are sets of n-tuples where each attribute value has a domain.

SQL databases call their version of relations tables, and, in that view, a database with a single table is still relational.

Now I don't think SQL databases are relational but the analogy still holds (I'd just say that a relational database can have just a single relation)

If you meant it this way and I misunderstood you, apologies, though I'm not sure I'd say most data is actually inherently relational (even though I do think the relational model is the best one we have so far for databases).

However, if you meant that most data has relationships (as the ones we enforce with foreign keys in sql databases) then I agree with you, and I think using database management systems that don't have good support for representing this type of relationships between data entities will only work in niche cases and will eventually cause more trouble than benefits in general-purpose use cases.

Nothing here says the data isn't relational. It strongly disagrees, with reasons, why it's not better represented as relational.

Personally I prefer the relational stance, and there are a lot of people who don't get it who say things like "this data isn't relational", but that's not the argument GP made.

I would argue most data is inherently(naively?) hierarchical(the document), relational structured data is a clever but unintuitive mechanism to introduce powerful analytic opportunities to a set of data.

Basically a document is a report, a large disjoint volume of information on a subject, I consider this the natural form of data because this is how it is collected and how most people think about it. relational is sort of like storing that data as vertical slices through your stack of reports. Not natural at all but much nicer for analysis across the data set.

In the real world of business, generally you want to store these pieces of information together to establish a historical record, not have references or links to other tables, etc. Links and relations are fragile, as anyone who's clicked through to a 404 can attest. Standalone documents last as long as the media that stores them.