I don't count a serial killer's happiness as better than his abject misery. So therefore happiness is not always better than misery, in my subjective opinion.
We have no trouble dismissing such a person...
I think this is where we differ. I have trouble dismissing the views of others as objectively mistaken, because I know of no basis whatever on which to do so. I can say subjectively that I don't agree with someone who wants to vomit, that I can't understand it, that it doesn't make any sense to me. All those things I have no problem saying categorically. What I can't say is that he is objectively wrong to want as he does and I am objectively correct to take the opposite view. On what basis could one make that statement? I am curious to know.