No, of course you don't have to share it. If you don't care about him, it's fine. About 150,000 other people will die today, none of them inherently less worthy than this one.

However, if you don't care about this particular death, don't barge into a comment thread and humblebrag about it. Ignore it and move on. It's not heartless if you don't care, but it's pretty rude to come in and post a comment like this.