Down South “salad” is just a means to add mayonnaise to things. The pear salad recipe has an interesting reference to “cooked” salad dressing. Cooked salad dressing is a mixture of dairy and eggs with other flavorings, thickened much the same way you would a béchamel sauce or a hollandaise. After cooking, these sauces were chilled and then used as a salad dressing. The eggs and dairy were readily available, but vegetable oils and olive oils weren’t as easy to come by. So why not make a white sauce you’d put on hot vegetables, and chill it for cold ones?