It is not semantics. A unibody car does not have a frame. It was started in order to save money and weight, then the car companies realized that people weren't buying the argument that it was just as "solid" or "safe" as a car with a frame (see my example of police departments above). They tried (successfully) to make the claim that it was better for the front end to "accordion" than remain intact, because passengers would be less likely to fly through the fukkin windshield. It has become universal practice because it saves money and weight.
A unibody car, hit properly, can be totaled in a fender-bender. I personally never allow my vehicle to collide with others, so it's not an issue for me.