But of course Dean (who is hurting and is hearing this through his own filter of “no one loves you or needs you as much as you love and need them”) is going to interpret it as “I don’t love you enough to save you,” instead of “I love you enough to respect your decision.” Just as Sam interprets Dean’s actions as “My needs are more important than yours.” And that’s heartbreaking.
I really like how you've put this and it nicely sums up my own thoughts on the matter.
However, as I was watching the episode, I wondered if the writers weren't actually favouring Dean's interpretion of Sam's words - I'm a dedicated Dean-girl, but I still thought that the way Sam's opinions were handled was a bit unfair by comparison.