Are we really making a tantrum about a default setting? One that is (or rather would be) a sensible choice? Or am I missing the bigger picture?

If the devs wanted to put some intrusive default settings (like a central image-upload checker) then I would understand, but this is a fucking boolean for whether to allow infinite scrolling on the bundled frontend.
This is what server admins are for: to config their servers in a way they see fit for their communities.

And about the content URLs. Later on they agreed on accepting it if someone implemented it well, even if they said they won’t work on it for now because there are more important things to get done (and let’s be honest, that’s true).