Because $KMX is not a car dealership but a car financing company. They will force, as much as possible, to buy using their financing. They don’t realize/ understand that is really driving some/ many customers away. I am not sure it really encourages people to finance through $KMX but it certainly drives people away.
Sometimes, organizations, like people have some bad habits developed over time and just can’t recognize and will refuse to change as long as possible.