It sadly is, but the core syntax of YAML IMHO is still nicer than any other. To that end, I wrote a parser that simply cuts out the crappy features leaving just the basic core (and added optional type-safety/validation):

https://github.com/crdoconnor/strictyaml

I also tried to write up a more extensive justification for anybody who scratching their head trying to decide which config format to use (including a "why not HOCON" paragraph):

https://github.com/crdoconnor/strictyaml/blob/master/FAQ.rst