Choosing different communities with the stated purpose is all about context: the policies of the mods, the policies of the admins, and the reputation of the instance. Yes, it isn’t a perfect analogy, but people need to shift how the think about the Lemmy/Kbin model from how they think about Reddit, and the example that seems to connect most easily with users is e-mail. Maybe a more subtle / apt analogy would be [email protected] has an obviously different context and significantly different content than [email protected], but the same stated purpose (and community name).
The problem is that it isn’t just the users who are confused about this: Lemmy admins seem to each have the goal of being “the place to be”, and Kbin goes out of its way to devalue off-instance content. I personally think (primarily) user instances should be separate from (primarily) content instances, but that would take a coordinated effort by the admins. We are starting to see some grass roots efforts at making that happen, though the actions of the admins may prevent that from taking hold.