They become pain points when you didn't write them, which is implicit in the article. Picking up somebody else's code always sucks, but JavaScript has a way of making it so much worse. There are so many elements, many of which aren't libraries but instead transform your code. If you don't know any one of them you can be completely lost, especially if it is so outdated that you can't get it to work.

You could write a similar story for any language, but JavaScript embraces all of them at once.