Comment by sudobash1

For those who want to disable middle-click paste, KDE already has this as a setting (of course it does, everything is a setting in KDE). Under "General Behavior" there is a checkbox for "Middle-click pastes selected text".

Personally, I find middle-click primary selection paste one of the nicest conveniences in Linux, along with Alt (or Meta) dragging of windows. But if GNOME made it a default-off option that wouldn't be the end of the world. Those of us who love it would quickly seek out the option to enable it. But I get the impression that GNOME tends to value opinionated simplicity, and I wouldn't be surprised if that default-off option just disappeared after a while.