COMPLETELY agree, kate, it is ALWAYS Sam’s choice to stick with Dean!! And he always does. I never thought Dean dragged Sam anywhere. But I do think that Sam comes back to DEAN and not because of hunting. At least not until later seasons. At this point in the series, I do think Sam still hopes for an end to the hunting life. Dean already accepted that there will always be another monster to hunt, but Sam has settled into that idea yet or at least isn’t seeing his responsibility in sticking with the life yet.
I think that is part of their lovely messed up dynamic: Dean cuts Sam loose for his own good, partially because he knows or hopes that Sam will be back, and Sam leaves, partially because he wants to be asked to stay, but knows that he’ll come back no matter what. And round and round they go.
Base line – they know they can count on the other when it matters.
I always felt horrible for Dean being stuck between Sam and John trying to be the mediator!!! If BOTH John and Sam would be better at communicating and LISTENING much of the ugly fights could be prevented.