That's a Javascript rant from 2015, and almost completely unapplicable to Rust. The rust designers were well aware of the disadvantages of various async implementations and have learned some lessons.

First he starts with a rant about the color of a function. In that sense, all typed languages have a color, aka the type of their return parameters. Sure, there a advantages to dynamic languages, but they're going out of fashion now for some good reasons.

Then he lists 5 more specific drawbacks of async code in 2015 Javascript 2015. All 5 aren't issues in Rust.

#1. Every function has a color: that's how typed languages work

#2. The way you call a function depends on its color: the rust compiler doesn't let you get this wrong and provides cut and paste corrections when you do

#3. You can only call a red function from within another red function: Use Future#poll

#4. Red functions are more painful to call: This is in reference to callback syntax in old node.js code and is fixed by the await sugar even in modern Javascript

#5. Some core library functions are red: The clause "that we are unable to write ourselves" is untrue in Rust; you should never have a need to drop down into C to write anything. And this is really just a variant of #3; if it's trivial to convert async to sync this wouldn't be an issue.