>> This gets to the heart of my problem with Prolog: it's sold as if it's logic programming - just write your first-order predicate logic and we'll solve it. But then to actually use it you have to understand how it's executed - "understanding why Prolog is backtracking in the first place".

Prolog isn't "sold" as a logic programming language. It is a logic programming language. Like, what else is it?

I have to be honest and say I've heard this criticism before and it's just letting the perfect be the enemy of the good. The criticism is really that Prolog is not a 100% purely declarative language with 100% the same syntax and semantics as First Order Logic.

Well, it isn't, but if it was, it would be unusable. That would make the critics very happy, or at least the kind of critics that don't want anyone else to have cool stuff, but in the current timeline we just have a programming language that defines the logic programming paradigm, so it makes no sense to say it isn't a logic programming language.

Edit:

>> At that point, I would just prefer a regular imperative programming language, where understanding how it's executed is really straightforward, combined with some nice unification library and maybe a backtracking library that I can use explicitly when they are the appropriate tools.

Yeah, see what I mean? Let's just use Python, or Java, or C++ instead, which has 0% of FOL syntax and semantics and is 0% declarative (or maybe 10% in the case of C++ templates). Because we can't make do with 99% logic-based and declarative, gosh no. Better have no alternative than have a less than absolutely idealised perfect ivory tower alternative.

Btw, Prolog's value is its SLD-Resolution based interpretation. Backtracking is an implementation detail. If you need backtracking use yield or whatever other keyword your favourite imperative language gives you. As to unification, good luck with a "nice unification library" for other languages. Most programmers can't even get their head around regexes. And good luck convincing functional programmers that "two-way pattern matching" (i.e. unification) is less deadly than the Bubonic Plague.