A couple of points:
Other teams that were suitors for ERod's services may well have been on that no-trade list.... by taking those teams off the table, perhaps it limited the amount of options they had to deal him off even more than we realize.
How often are deals actually killed via a no-trade clause? They appear to be mostly used as leverage for players to extract more out of teams, but I honestly cannot recall a similar incident of a player actually killing a deal like this. Even if ERod's a headcase, I'm not sure that, in and of itself, you just limit yourself for an event that is unlikely to occur and yes, I doubt very few, including the fans who are currently the loudest about how this went down anticipated this playing out this way.
If there weren't other teams who were making acceptable offers or providing the value that the Dodgers appeared to have been willing to provide, why not make the 'calculated risk' to go for the best possible return as opposed to just accepting something that team considered substandard?