> Then they need to get over that if they want to learn to code or use scratch.
This is the right attitude to have as an aspiring programmer, but exactly the wrong attitude for someone who creates the tooling or documentation for helping aspiring programmers learn.
But it is the right attitude for someone creating tools for other proficient programmers to do even more advanced things. We won't advance the state of the art by handicapping yourself through catering to extreme beginners at every point.
In other words, the target audience of a Promise library for JS are people who know JavaScript and understand async. Trying to explain the basics of JavaScript, or programming in general, in that library's documentation would be a waste of time for everyone involved. A beginner has plenty of resources to learn from to reach the appropriate level, at which point they'll be able to wield the Promise library in a useful and responsible manner.
This is the right attitude to have as an aspiring programmer, but exactly the wrong attitude for someone who creates the tooling or documentation for helping aspiring programmers learn.