Because SQL looks and is more simple: plain English words that are easily recognized, with basic queries (select from) that can be taught in less than an hour and then build on it. Now let's look at SPARQL: everything screams at technicality. Curly braces (I'm not sure a non-programmer even know how to type this). Then the variable name prefixed by ?. Then the need to understand what is an URI and how and why prefixes are declared, not to mention the sheer fact of using URI instead of a simple names such as one found for database columns. But even that isn't enough knowledge to start writing the simpliest query. One also need to be taught about RDF triples.

So no, every query languages are not born the same. SPARQL is overly technical and requires a lot of knowledge to do even the simpliest things.

Well one reason why someone might learn SQL without learning how to program is that you can get jobs for it.

Ah, but the response might go, lots of people learned SQL when there weren't a lot of jobs for people who knew SQL.

Yes, my response would be, but that was a long time ago and the incentives for people to learn technologies have changed, and I do not think a significant amount of people will learn SQL without learning to program henceforth; at least not amounts significant enough that anyone will say "Well look at that trend!".

here there can be several responses so I won't go through all the branches, but in the end I don't think there is going to be an interest in learning Sparql in people who are not programmers or at least programming adjacent professions, and from what I see there hasn't been that much interest from people who are programmers.