wicked-nursery-rhymes replied to your post:maybe when a character has spent the majority of...
What I don’t understand is why this only applies to Dean. Why is he the only character getting called on to prove his love for others? What is so special (i.e. lacking) about him that nothing seems to be enough?
I wonder if it has something to do with how other characters are initially set up, and whether that contributes to them having a different baseline of what's considered showing sufficient care. I think using someone's sacrifices to judge how much they love someone, and comparing degrees of sacrifice towards people to compare amounts of love is a crappy way of looking at things, but it's a pretty common fandom trope, so… having a big gap between what a character will do for random person x and what they'll do for important, special, beloved person y can be taken as proving how much they really love person y. So it matters not just what they'll do for person y, but also what lengths they'll go to for person x, because the contrast is important.
John was mostly absent and clearly motivated out of revenge, so while he was putting his life on the line hunting and saving people through hunting, it wasn't really about him risking his life for the PiP.
Sam had left hunting when he was first introduced, so he wasn't out endangering his life at that moment and was resisting going back to it. When he did start hunting again, it was heavily paralleled with John's revenge quest, and in the first season he was often more focused on finding Dad/killing the demon than the saving people part.
Cas, although he pulled Dean out of Hell, did it because the angels needed to use him, not because he was in the business of saving people from Hell. There was quite a bit of Dean calling out God/Heaven/angels on letting humans suffer, and pointing out that they've stood by watching an awful lot of terrible things happen. And while Cas wanted to stop the apocalypse, he wasn't really shown out there putting his life on the line for random humans.
But Dean, he was shown throwing himself into danger for people he didn't know, right from the start, and in 1x02 he says he hunts to keep other people from being hurt, as part of the conversation that has that iconic 'family business' line.
So, maybe Dean is expected to go farther because he started out risking more of himself for unknown people, so he has to do more in order to make a contrast with what he'll do for Sam/Cas/whoever, in order to show that they're more important to him than strangers. But if John/Sam/Cas are first established as not as willing to risk themselves or their desires just for the sake of a random stranger, they don't have to sacrifice as much comparatively for Dean in order to get a contrast to prove that they love Dean. John's an asshole who pretty much uses people to advance his revenge quest, so one time he can say he shouldn't have used Dean the way he did (…and then go on to perpetuate that dynamic) and he's shown his love. Sam wanted to leave the PiP to probably die in Scarecrow in order to track down John, so when he gives up the lead on John to come back for Dean, he's shown his love. Cas is willing to kill people as collateral in the Heaven/Hell war, so when he says he doesn't want to hurt Dean (even if he then does anyway), he's shown his love. Dean has a lot of scenarios right from the beginning where he's willing to go really far for people he doesn't know, some of whom he doesn't even like, so his bar is set really, really high. I mean, going back to 1x02, Dean wants to save people from the monster so he goes into a remote forest where people were attacked and where he winds up captured by a cannibal-monster, and then almost as soon as he's freed he uses himself as bait for said monster to try to get everyone out safely and destroy the danger. That's a high bar to beat in order to show that Dean really loves someone by comparison.
