Dean is allowed to refuse to do things Sam’s way.
Dean is allowed to disagree with Sam.
Dean is allowed to be angry when Sam abandons or betrays him.
Dean is allowed to keep his feelings to himself.
Dean is allowed to have feelings regardless of whether they are what Sam thinks they should be.
Dean is allowed to call out even a loved one for hurting him or betraying him, especially if they keep doing it.
Dean is allowed to be afraid or nervous that they will do it again.
Humans are allowed to do all of these things, and as a person, so is Dean. None of these make Dean controlling, abusive, or cruel. Framing it as such what an abuser does to keep their victim in line. It’s a method certain people use to manipulate someone else into silence or compliance. Dean falls for it because of years and years of formative, psychological abuse, but that doesn’t make it even remotely true or right or even acceptable.