So this is a damn old post and I do not think anyone is going to be reading my reply but I need to write this.
The thing I do agree with you that Dean is very hard on Sam but there are plenty of reasons for that and they may not be completely justified to some people but they are justified to me.
Since Dean was a kid, he has been looking out for Sammy it was his job and I dont know which season it was but it was during earlier season where Dean that more than his job thats who he is. And I think in the beginning he did not expect Sam to return that favour you know? but then whem Sam did everything he could to save Dean from going to hell in season 3, Dean realised that his brother would do the same and I think after that he expected Sam to always look out for him just like Dean did you know?
And then when Sam did not look for Dean after purgatory, Dean was hurt because like I said he expected his brother to try and get him out regardless of the promise they make that we wont look for each other. It hurt him I think because he was fighting a tough battle down there while his brother was living his life and we all know if Sam was down there, Dean would have tried everything to get him out. Dean expected him to get him, we could say that Dean should not expect that and then make Sam feel guilty for not meeting those expectations but Dean thought that Sam would return the favour you know?
And then when Sam said given same circumstances, I would not have regarding the whole angel think in season 9, Dean was really hurt.
So what I am saying is that no matter what Dean says, he wants Sam too look out for him you know? In Season 10 yes he was mad at Sam and writers never addressed it and idek if its true but knowing Dean since season 1, I think deep down he was happy that Sam was trying to save him you know? He was mad that Charlie got in crossfire and got killed but somewhere Dean was happy that Sam was trying.
I understand Sam's point of view but I think Sam feels guilty because he did nit look for his brother when he knew that his brother would have looked for him if situation was reversed. At the end of the day as much as I hate to admit, Dean needs Sam more than Sam needs Dean. Sam loves his brother, but I think Dean fears being alone because he cannot imagine being without family.
So all I am saying is that yes Sam has been guilt tripping a lot and that sucks but his guilt tripping is sort of justified given what has happened.