This is a good example for bad design. Apart from the odd shape (this is debateable - perhaps some people like the design) the choice of the exterior material is not to be considered a good one, concidering the vehicle’s exposure to the elements (dead bugs, tree sap, salt, dust, dirt, etc.) is nothing out of the ordinary. These are normal things an ordinary vehicle is exposed to.

Maybe Tesla could sell accessories like some kind of panel covers to protect the body of the car, in a similar way phone covers are being sold to protect phones. Which in itself is also the result of bad design: not only a phone cover hides the original design of the phone, the necessity to use a cover on a phone shows that the phone probalby is not built strong enough to withstand daily usage, like falling on the ground or being carried in a pocket.