On a phone, you drag the page so when your finger moves up, you are scrolling down. MacOS has had this be the standard for a long time.

Changing the direction makes touch scroll act like you're click-dragging on a scroll bar. when your finger moves down, you scroll down.

Before 10.7, the scroll behavior acts like you've grabbed the scroll bar and your fingers drag it, so moving your fingers down makes the scroll grip move down and the page content move up. Moving your fingers left makes the scroll grip move left and the page content move right. The scrolling paradigm is that your fingers grab the viewport and move it with respect to the content.

In 10.7 and later, it instead acts as though your fingers are grabbing the content and moving it around within a stationary viewport. So moving your fingers up pushes the content upward. So the scroll interaction is like the direct interaction on a touchscreen, but via a trackpad instead.