This. There is no use writing "X is better than Y" without specifying what metric(s) you're using. If it's about human legibility or editability, YAML is better than XML. On the other hand, I would never use YAML as a machine-to-machine data interchange format; for those, JSON or XML are superior.

I also had to laugh at this statement:

the YAML specification has all these features that nobody ever uses, because they’re really confusing, and hard, and you can include documents inside of other documents, with references and stuff

That's a pretty funky argument to use in favour of XML.

As I am fond of saying, there's a common misquotation that runs "YAML is easy for humans to read". The full quote is "YAML is easy for humans to read wrongly".

Best parsed with a ruler on the screen.

I can't parse it.