I’m trying to think about other celebrations you might be referring to. For example… Hitlers death wouldn’t have been celebrated simultaneously due to being limited to the methods of news communication of the time - back then it was radio, telegraph and film so it wouldn’t have been celebrated at the same time. Today, we have smartphones with push notifications. Your other point is spot on, tho… For what ever reason, a person full of hate seems to live longer out of spite.