You should never buy one tire anyway. You should always replace at least pairs.
As another commenter pointed out, this is quite common on performance and luxury vehicles because it has handling advantages. If you're buying a luxury car, you're by definition choosing to pay more than is absolutely necessary for (what you consider to be) a better experience. The tires are part of that. You can argue that the line should be drawn elsewhere, but it's not arbitrary, and it's very much in line with the market segment they're going after.
Performance vehicles I disagree. Handling choices are up to the mechanic/driver and you want to give them options but also make their maintenance choices simple. You should have a wide range of tire options on a performance car.
It's a SUV. They get used to tow boats, take science-fair projects to school, and take the family on vacations. They aren't used for track days at Road Atlanta.