I agree that Jody said the guys were right, in connection to being (too) emotionally involved, but they really didn't need to include that line. As for emotions, the way I read what happened is that Jody's emotions led her to save Alex and do "the right things", where the Winchesters' "rationality" would have led them to end the life of someone who'd suffered a lot, while blaming her for it. As far as I'm concerned, Jody's emotions were an asset.

I think that dialogue fell flat because we (as in long term fans) have good knowledge of the past

I agree, and I do like the guy's writing (though my fav writer on the show today is definitely Robby).
But is it really that much to ask, for a writer on the show to actually get to know canon, if not fanon (and also fanon,,,)?
Or, OK, if he's not a regular maybe he isn't free to get to know canon - at least the show runner should take care of the continuity and depth of the characters? Ugh. [/ rant ]

I think it was mostly done to signal Sam's concern for Dean and acknowledging how Dean is changing (hee- which we could easily see without Sam saying anything...).

Agreed.