What you are offered is determined by what cars are rented, or returned, by others. This applies to all companies. There seems to be an assumption that they have Ford Tauruses but aren't renting to them to you. You can always ask what is available. When renting a full size car I've been offered a Toyota Camry, Chevy Impala, Nissan Altima. Once, with Avis, a Buick Lucerne. And recently, with Alamo, we got a Dodge Charger with a larger engine (nice power, but sucked gas).
Sometimes an upscale model of a particular car (e.g., Chevy Impala with leather seats and add-ons) may be considered a premium car. A Toyota Camry seems smaller than a Chevy Impala to me, but it's still considered a full size car. When I've rented a "standard size car" (Ford Fusion or similar), I've gotten a Fusion, and also been offered a Camry or other similar cars. The Ford Taurus is merely given as an example. It doesn't state that they have more of those than others. I've never been offered a Malibu (which, I agree, is not a full size car). If you don't like the car assigned to you, you can ask for another, upgrade or go somewhere else. Thems are the breaks.