But that's rather missing the point, isn't it? The premise is "Under circumstances where encryption is not a viable option, what secure communication methods might be possible?" so responses that ignore the premise, like "just use encryption" or "just don't get into such circumstances", aren't the most salient critiques.
Two points: First, this was from 1998 - back when "exporting encryption" from the US was punishable as exporting weapons. Secondly, this is proposing a communication scheme where there is no "encryption/decryption key" for the NSA to coerce people into handing over.