I would consider that death should not 'exclusively' be seen as a positive thing but more of a neutral thing. Death itself can be positive in a situation where life is only full of suffering and the person has more suffering than pleasure. However, I would not exclusively label death to be positive especially in situations where there are people really enjoying life, because in such situations, death would be depriving them of continued pleasure and future pleasures.
I say that death is considered more of a neutral state because it is a state of nothingness (assumption of no afterlife but just non-conscious and nothingness). While I am an atheist and I believe that there is likely nothing after this existence and that once I die, I cease to exist. Life is a state of existence and consciousness and there could be a positive experience (mostly pleasure and little suffering) or a negative experience (mostly suffering and little pleasure), so death would bring that to a neutral.
I will say that I do agree that death should not be stigmatized and demonized the way it is in society, especially in modern society. Life should not always be seen as a virtue, but more as something that is thrust upon every living thing in this world.