Well that’s news to me about some secret karma score. But I doubt that’s the goal here since it has no relevance to anything currently.
I disagree with basically everything else you wrote. This is a news article and a world news article. It’s not an advertisement for shoes or something inappropriate. So what is wrong with posting it in multiple relevant communities? If you don’t like news, then yeah, you’re not going to be interested. But that’s on you to set up your feed so that you get content you are interested in, and not content you aren’t interested in. I don’t understand people who just view the main feed and then complain that not everyone shares their interests. That’s always going to be the case and there is no way around it except by customizing your feed.
Different communities definitely have different content, so I don’t know where you are getting that from. Maybe you need to check out some different communities. But obviously there’s going to be a lot of overlap between different news communities. You could argue that they are a bit redundant, and yes, that’s true, but that’s the nature of the fediverse. Different instances sometimes have very similar communities, and so they do share a lot of the same content. This is also true on Reddit by the way, you just have identical communities with slightly different names.