Well, for one thing, I'm not Catholic, so it's not my holiday. I'm sensitive to things like that. The saints mean nothing to me, and the dead don't live.
For another, I see enough decaying bodies and mortality in the course of my life and work. I don't need the reminder. I am intensely aware of the fact that we're all engaged in a losing war with all the little things that want to eat us and will eventually break our structure down and denature us. Y'all enjoy a frisson of horror because you're going back to a world in which it's not true. But there is no world in which it's not true, and I don't mean to pretend that there is. We are rotting, here where we stand.
For another, deceiving others about our true nature? This is supposed to be festival occasion? It's an occasion I spend my life trying to escape.
So, sure, I'm a killjoy. There are some narrow joys that impede larger ones, and I kill those with gusto. And I don't like deceiving children, or playing on fears. Again, it's the daily stuff of life: it's what people do every day. Enough already. We can play at fear if we ever reach a time when being alone with ourselves for twenty minutes without distraction doesn't terrify us. Till then, we have enough real fear to be going on with. We don't need to invent any.