In my experience learning a bit of OCaml after Rust, and then looking at Haskell, the three aren't all that different in terms of the basics of how ADTs are declared and used, especially for the simpler cases.
Another way of phrasing my query is that given these are all basically ML-style constructs, why would the examples not be ML? And I was assuming the answer to that is "the sorts of people reading these blogs in 2024 are more familiar with Rust"