I think it has more to do with preference than hate. For me particularly, I don't care much about how things are stored. I just make sure to exporr/backup regularly, and if anything breaks, it's an easy and mostly painless fix.

I tried Obsidian once, and while I did like it and the UI is light years ahead of Joplin, I guess I'm just used to the Joplin experience, so I saw no need to switch.