In UX theory we have a concept called personal schema. It's how you think the world should work based on your personal experience.
So, in this case, if I'm looking at a sorted list I expect the switch motion to match the relative direction I want to move within that list.
And, because the HMI is designed to have the radio as the secondary screen , home as the primary, it makes sense to have up as move numerically increase because you can't see the list. And when you can, to match the motion with the desire.
The issue is muscle memory. How would you keep the motions the same...
You could reverse the list so it's descending but that means the list is always resorting. Very, very bad.
You could rotate the steering
wheel button to be right to left but I personally think this is hard to find with my thumb. But then the list is visually vertical so this takes more thought processing for an interaction.
You could rotate the button and the UI so everything is right to left. Which solves all the issues but this doesn't fit their HMI UX.
So in the end, I like that they put thought into the 2 cases. Me, I'd prefer a right to left, horizontal list, as so many of my cars have had this it's my expectation.