I commonly browse all by new, and I block users who crosspost any given article to more than one other community. To me it’s almost always a sign that they actually don’t care about the topic or contents, but instead their own post count and user recognition.
This stance would make sense if groups were in any way tree-structured.
They aren’t.
The two groups I mentioned above are (I think) on entirely different instances. (If they aren’t, they could be.) There’s no hierarchy.
You are right. I am, as always, idealizing.