It’s because ppl are not using it correctly, it was designed for configs and now it’s being used as a programming language… a language without types and debugger. It’s frustrating devs because they find the issue at the deployment time, not the compile time.
Personally I did never pick the YAML as a first format for the configs, only my ruby friends did that.
It's also terrible for configs, for many of the reasons specified in the article.