For most of Windows history it was impossible to switch scroll direction without messing with the registry. Seeing how long it's taking to make it a user-accessible setting I assumed it's because either the way Windows handles scrolls is incredibly borked, or some Microsoft manager is religiously opposed to it.

Seeing how now that they finally implemented it, it doesn't work in OneNote and other random apps and it's called "Down motion scrolls up", I'd say it's both lol.