So the claim is not well supported at all by the article as you stated, in fact the claim is literally disproven by the article.
> uv is fast because of what it doesn’t do, not because of what language it’s written in.
The fact that the language had a small effect ("a bit") does not invalidate the statement that algorithmic improvements are the reason for the relative speed. In fact, there's no reason to believe that rust without the algorithmic version would be notably faster at all. Sure, "all" is an exaggeration, but the point made still stands in the form that most readers would understand it: algorithmic improvements are the important difference between the systems.
The specific claim I was responding to was that all of uv’s performance improvements come from algorithms rather than the language. My point was just that this is a stronger claim than what the article supports, the article itself says Rust contributes “a bit” to the speed, so it’s not purely algorithmic.
I do agree with the broader point that algorithmic and architectural choices are the main reason uv is fast, and I tried to acknowledge that, apparently unsuccessfully, in my very my first comment (“I don't doubt that a lot of uv's benefits are algo. But everything?”).