In general I am sympathetic to whitespace - I find the argument "whitespace insensitivity means the code now contains two conflicting sources of truth: whitespace which the programmer uses, and braces which are the only one that matters because that's what the computer uses" to be compelling.

But the whitespace sensitivity of YAML is particularly bad because of e.g. Helm. Templating a whitespace sensitive language with string interpolation is such a terrible idea.