my problem with it was more that I didn’t believe that Sam’s anger at DEAN was that deep. THAT is the part that was overstretched for me.
I get that there had to be a certain resentment from Sam’s side to get the ghost to feed off and Sam definitely has an anger issue but I believe most of that is directed at John.
The anger Sam harbors for John and Dean is definitely as complex as Dean’s feeling of guilt is. I think there is jealousy involved – Sam being subconsciously jealous that Dean IS the better hunter and therefore of more value and help to John for example. Sam lashes out at the other two but I believe is also in large parts angry with himself for not doing anything to rectify the situation.
I’m not trying to defend Sam beyond reason here. He acted AWFUL in this episode and didn’t do enough to make up for it. It left a definite sour taste behind. I just think that the writers over did it to create more conflict than there ought to be.