The result makes sense, but they could have put it a little better. A printout of an email is pretty useless when it comes to tracking down a scam like this.
Unless you printed every single header and the source code of the email, they wouldn't really be able to do anything with that sheet of paper. They could have said it better, but it's a pretty geeky subject and maybe they just did a poor job of saying so.
It's interesting that Yahoo blocked you from forwarding it - It makes sense, if a little overzealous. As you've seen, it makes giving it to someone who can do anything about it a bit of a challenge. I don't use my Yahoo account, but if there was a way to save the email to a file, then maybe you could forward it as an attachment.
They coulda done a better job sayin' it ... but a printout wouldn't have done me any good in hunting down a scammer. Ya need IP addresses and such, not the contents of the email.