I know that I'm biased, which is why I like to be told when people feel that I am. That being said, I don't care if my bias causes me to declare a guilty person innocent, only the other way around. You could even say that the previous statement is biased, and you'd be correct, except that it is very intentional.
which makes you unqualified as any sort of "judge"
Theymos, you really need to find someone else for this.
is biased in some way or another, and to think otherwise is naive and foolish. You can't get rid of bias anymore than you can get rid of emotion or opinion. Best way to deal with bias is recognize your bias so you can adjust your actions to compensate for it. Would you rather him lie and say he isn't? None of us have ever claimed to be unbiased, we do try our best to not let it interfere with our duties.
As for the OP, Nefario isn't responsible for the actions of others. If Usagi/Diablo is a scammer, you don't blame the middleman unless you can prove he knowingly aided and abetted it. Innocent until proven guilty and all that.
As for Goats issue, I can see why Nefario wouldn't send him the bitcoins if the address was altered in any way, even if it was "just" a space. And putting his email entirely within quotes was odd and uncharacteristic of usual communications, and would send up red flags for me too.