People often say that before they realize how complex and messy real-world Haskell looks like. The indentation-based rules aren't even defined anywhere except via imperative code in the implementation.
> The effect of layout is specified in this section by describing how to add braces and semicolons to a laid-out program.
I wasn't going to actually read that in detail to see if it makes any sense, though, but it looks very detailed :).
Anecdotally, in my years of haskell at separate places, I had to debug/repl maybe had to repl once or twice. I wish I could say that of mycurrent java gig.