The dead are gone, and do not care, or matter. It is funny that humans celebrate theirs, with cemeteries and more. To bury themselves is exactly right.
Discussion
It's called humanity. (They certainly don't care, as you rightly point out, they are dead). They certainly matter in the eyes of those who remain though.
Which reminds me of a quote. "The dead don't know they are dead, it is difficult only for the others. The same is true of stupid people".
So there you have it😬😂.