When the touchpad is set to emulate a mouse scroll wheel while using a circular gesture, swiping clockwise is scroll down and swiping counter clockwise is scroll up. Of course, you can change this if you want:
Steam>Settings>Controller>Pair and Manage>Desktop Layout>Edit>Edit Layout>Trackpads>Left Trackpad Behaviour>[gear icon]>Invert Swipe Direction
Or just swap the "Clockwise Command" and the "Counter Clockwise Command" under Steam>Settings>Controller>Pair and Manage>Desktop Layout>Edit>Edit Layout>Trackpads>Left Trackpad Behaviour
But regardless of the fact that it can be changed, there must be some logic to why the Steam Deck touchpad behaves that way by default, right? Help me make sense of why some dev team at Valve decided that the default should be "clockwise=down" despite these other common scenarios in which "clockwise=up".
I think it's a matter of perspective.
In your time example, I see it as time going forward, not up. It's progressing. When you scroll with the steam deck you're "progressing" through files, which are normally organized in a descending, downward way.
I had a coworker who would say "scroll up" or "scroll down" depending on if he wanted the document/content to move up or down.
I would say scroll down the page if I wanted to see more of the information on the bottom of the page.
The scroll bar needs to move down
... is that not typical?
I think he means that the coworker said "scroll up" to mean the virtual page moving up - I.e. when the viewport scrolls down.