Mac UI as generally understood didn't involve moving windows around yet, not really[1]. "Window management" at the time was limited to the paradigm you'd see on the mac plus screen where you'd have one app window and some dialog boxes. Yes, you had a button to close it, but the paradigm didn't match the needs of the big workstation screens on which X11 evolved.
[1] These were the dark days of the mac. It was falling behind rapidly and the failure was accelerating. Jobs would walk back in the door within months of this moment too! Again, Windows 95 isn't felt to be notable in this community of true believers, but it was absolutely a bomb in the market as a whole. It changed everything, instantly.