It's only "reversed" if you consider the other direction "normal". Either one makes sense: Mac acts like your finger is moving the page itself; X11 and Windows

It's only "reversed" if you consider the other direction "normal". Either one makes sense: Mac acts like your finger is moving the page itself; X11 and Windows act like your finger is moving the location indicator on the scrollbar. Either one makes sense a priori, but once you're used to one the other becomes intolerable.