I don’t use Gnome, but they hate to expose settings in general it seems and like to dumb down everything (and that is why I don’t use it). The issue here is that the you need KDE, Sway, Niri, Xfce, etc all to implement a setting for this. Middle mouse paste is useful and has been standard on Unix-likes for decades. There is literally no reason to remove it.

No, it was your assertion that a wheel being too fiddly. It seemed quite broad (stating it as an universal truth). It might be for you, but not for most people (but you wrote it as an unqualified statement).

Not true, if there is no user visible setting for it. Changing a hidden gsetting via a command line is essentially removing it since it will likely bitrot and then be fully removed in a few years.

For many people this is a non-issue. I think this a case of just accepting we are different and don’t need to force our view on everyone else.

Maybe 15 years ago I had a mouse with a tilting scroll wheel (for side scrolling), on that one I did have issues with middle click, for about a month until I got used to clicking straight down.

So maybe it is just a question of practice? Maybe not. But since both options exist there is no need to get upset.