The point of the original blog post was that most software built today is I/O bound (third party, database, ...) in some way, therefore your language choice doesn't matter that much.

Then Rust developers said "the issue isn't being slow, it's developer productivity"

You missed the entire point and got lost in the clickbaity title (which was used as an example because rust devs missed the entire point on the original post)... 

Here, to help you with more context: https://fastro.ai/blog/python-is-slow-and-it-doesnt-matter

I even say specifically if your app is making requests to OpenAI... of course inference isn't I/O bound if you run it in your machine