I saw one recently in a linux community where a user complained about multiple “I ditched Windows” posts. I’ve seen requests for stickies in some gardening communities.

That’s something that the moderators need to take action on, isn’t it? Don’t get me wrong, unmoderated communities is a whole issue on its own, but it doesn’t seem linked to the community separation.

But they shouldn’t have to merge.

They don’t have to, they can. But them being unwilling to merge similar communities seems strange, except if they can’t agree on instance due to the instance politics.

Cooking communities did a few months ago: https://lemmy.world/post/7578470