I think there are some excellent posts here. The dozy embrace is certainly one of the most poignant moments in the movie - to see Jack after his confrontation with Ennis at the lake flash back to a time when they were unencumbered by the complications of their lives after that blissful summer, only to be shoved back into the here and now - Ennis driving away, leaving Jack bitterly unhappy.
It seems Ennis was always leaving Jack because responsibilities were calling.
I don't want us to forget Annie Proulx's version of the dozy embrace, though. I think the movie somehow softens and romanticizes it in a way that the short story did not:
"Later, that dozy embrace solidified in his memory as the single moment of artless, charmed happiness in their separate and difficult lives. Nothing marred it, even the knowledge that Ennis would not then embrace him face to face because he did not want to see nor feel that it was Jack he held. And maybe, he thought, they'd never got much farther than that. Let be, let be."
Do others think that the film minimizes this aspect of their relationship, focusing more on the affection and happiness of that idyllic time on the mountain and less on Ennis' inability to accept himself and his love for Jack?