People always say that beautiful things are good, Or that "Beauty will save the world" as Dostoevsky said.

But... What about these?

One would call them morbid beauty, because death/destruction and beauty are intertwined in these images. Many of them do not even contain a speck of "good." Yet they are still beautiful.

People confuse beauty with goodness, forgetting that even death, killing, destruction, and evil can be beautiful.
Hannibal would be a great artistic example as to why beautiful is not equivalent to good.
Another example, one from the real life, is to watch any predator (a carnivore animal) during a hunt. They are absolutely beautiful and (not but) morbid.