If anything, that sounds like an argument in favor of significant indentation, not against it. Humans and machines read differently, yes, which is why we tend to add whitespace and indentation to code even for programming languages where it’s not significant. We do that expressly because it makes the code more human-friendly, so it’s quite the opposite of ignoring their differences.

I think YAML has its fair share of design flaws, but I don’t think significant indentation is one of them. It may not be a programming language (which may be debatable), but there are plenty that use syntactic whitespace.

Not sure I’m following the jump from significant whitespace to machine code. How are those related?

You’re going to indent your code anyway, so why not let the indentation carry meaning?

The joke’s not about Firefox; you could swap in any Linux program.

It’s perhaps not as featureful as others mentioned but if you like Rclone then Round Sync is a solid option.