My point was not that this was absolutely hard, but rather that's way too hard for the totally mundane thing I was trying to accomplish---namely getting public data from a US-funded statistical agency into a form suitable for further statistical analysis (which is the whole reason they make this data public).
Also, I don't see how it's ironic that I used Python---it seems irrelevant. Whitespace in Python has a well-defined, commonly understood purpose; using tabs or spaces to indicate hierarchal data relationships is not at all standard, presumably because it creates messy dependencies across rows of data.
The reason indentation to imply structure doesn't make sense for datasets is that in data analysis you are constantly subsetting and sorting data at the row level---something you generally don't do to the lines of a compter program.
FWIW, I find it ironic that the author is complaining about whitespace-implied structure in his source data, yet uses Python.