All functions are not coloured, don't try to wriggle out of it by generalising. This article is a specific complaint about Javascript. Javascript is a hack on top of a hack. Its async/await is crap. Javascript requires this "colouring" in a way that C#, Java, Go, Python, Ruby, C, C++, Rust, etc. don't, because they don't have to pretend they're a single-threaded event processing loop, while Javascript does.