Doesn't seem like anyone even asked what type of punishment system the Edo had, in the event one of the crew inadvertently broke a law. They were too excited to get down to the horny planet.
Yeah, and naturally, this very important duty would just be dropped at this point... Yar: Yeah, listen we've been reviewing your laws and we can't find anything about actual punishment for crimes. Could you fill us in? Edo Representative: No. Riker: Sounds safe to me, Lieutenant. Let's go, I have a date with that one blonde tonight. The Edo may have been dicks about this, but the senior staff of the Enterprise shouldn't get a free pass for being stupid.
Maybe they were stupid. But that doesn't mean Wesley should have died for it, that Picard should have allowed the Edo to execute him, or that the Federation is a terrible cultural imperialist for extracting Wesley from Edo custody.
I wouldn't let Wesley die. But, I wouldn't kid myself by thinking that extracting him from the situation was the right thing to do either. The Edo didn't force the Enterprise to send people down.