There are plenty of memory-safe languages equally suitable for similar CLI tools and, arguably, easier to write than Rust.
This is changing, happily, but OCaml I always viewed as kind of an elitistic intellectuals club. Happy to be proven more and more wrong lately, though!
I am looking forward, eagerly, to OCaml 5.0 and having an amazingly fast compiler with solid multicore runtime system support! It's very likely I might abandon Rust for OCaml when that time comes (8 - 12 months).
Instead, I think it comes from the fact that when it was first developed in the 90s, it was viewed in the context of C (and this attitude has carried over somewhat to the modern day where it makes much less sense). For example, building non-trivial projects with just the compiler is very painful from most modern perspectives, but it's very similar to what you have to do for C.
What you say is fair. It seems that OCaml's niche with time moved from competing with C to competing with Haskell and Rust -- at least from where I am standing. Maybe some members of the community aren't OK with that goalpost moving. That would be understandable.
But to be fair, I like OCaml more than Rust but I got very spoiled by both Elixir's and Rust's tooling -- both are excellent enablers of productivity.
Once OCaml overcomes this barrier (and introduces multicore) I am definitely going in, neck deep! :)
Another factor is that creating a language (Rust, Go etc.) from scratch lets you have nice unified tooling to an extent that is probably just not possible with languages with baggage. So I doubt OCaml will ever manage to be quite as seamless as those, but IMO it's already gone from significantly worse tooling than e.g. Python/Java to significantly better, and is still improving all the time!