smart supernatural blogger………tell us your thoughts upon the dean would always choose sam arguments…..please
The principal argument against this reading is simple: "Dean always choosing Sam" is not canon 😎
Most of the scenes used for this are something pressing a gun at Sam's head and going "you have to choose Sam now or he'll die" and Dean not shrugging it off and leaving carelessly and casually let Sam die, which is… normal actually? Sam is his younger brother so Dean cares for him and doesn't want him to die. Obviously in life-or-death situation, he will reassess his priorities and work to save his brother. It's not so much as a choice as blackmail. Besides, the canon pattern of it mostly shows Dean being ready to sacrifice his personal comfort and well-being. Like that time when he decides to cut ties with Sam for a while in season 5. It'd have lasted longer if he didn't get the whole your-brother-will-die-and-the-world-will-end speech. Or in the flashbacks of 9x07: Dean wanted to stay with Sonny, but it'd have meant leaving Sam alone with John.
As for Dean being ready to trade his life for Sam's: John hammered in Dean's head since he's 4yo that Sam's safety is his responsibility and the most important thing ever, and Dean believes his life matters less than anyone else's… including civilians' he doesn't know and he'll never meet ever again (saving people is literally the only saving grace he finds in hunting).
On the other hand, if the price for Sam's life is other people's life, then Dean will not choose Sam. It's shown time and time again.
When Dean learns, in season 3, that going in Hell means he's going to be turned in a demon and harm people, he searches for a way to break the deal even if it means Sam will die. In 5x13, Dean agrees with Sam that they should convince Mary to not have kids (= trading his life and Sam's for their mom's). In season 6, we learn Dean searched for a way to save Sam from the Cage without freeing Lucifer. In 6x11, Dean stops his bet with Death to save one civilian, knowing it'd doom Sam.
In season 8, Dean stays one year in Purgatory to search Cas. In 13x21, Dean herds a bunch of people to safety instead of (foolishly) trying to save Sam. In 15x19, he's ready to trade Sam's life for the world.
