Note that The Whitespace Thing actually preceded F#. (Mike and I were in the same fraternity, I remember talking to him about TWT, and we haven't talked much since our college days, which pre-date F#.)
IIRC, Mike was also doing a bunch of stuff with a Jabber client in OCaml around that time.
OCaml syntax is whitespace-insensitive. You don't need to worry about indentation, copy-pasting code snippets, etc. I think that makes for a better experience especially for beginners when the parser is more forgiving.