If you have eyes, you will be able to see that power dynamics between Sam and Dean are not equal. Yes, they are brothers. But considering last seasons, when the show actually affirms that Dean has more rights to Sam’s body and life than Sam himself (S9, whole Gadreel thing), when it’s very clear that Sam wants so hard to overcome the power dynamic, but when Dean is still domineering Sam like in the 14.03, to be honest, it’s not weird to feel uncomfortable with the scene where Dean’s verbally bashing Sam because he didn’t like Sam’s physical appearance.
If they were normal brothers, maybe the scene would have been cute. But their power dynamic is not like that.