The story is this, to the extent of my understanding: US citizens are free to sell such manuals within the US. The seller refused to send the manual to Oleg on his russian address, so some american guy on a game forum agreed to buy it and resend it to Russia. And in doing so the US espionage law was broken. Dura lex, etc. Had he just scanned the manual and put it anonymously online, all would be ok, I guess.
