Well if you bothered to read the link Elon had in one of the tweets in the twit stream you should know your perception of it is very wrong.
In there it has a very simple but clear explanation of what polar moment of inertia means for handling.
***Meaning: In the car world, this term refers to any car's resistance to turning. To figure out an individual car's polar moment, you need to know the individual weight of all components of the car separately -- as well as each component's distance from the car's center of gravity. Then you multiply the weight of each component by the square of its distance from the car's center of gravity.Therefore, larger polar moments of inertia occur when individual components of the car with heavier weight are further away from the car's center of gravity. If you're a racecar engineer, you already know this. If you're a car enthusiast who just wants to drive better on the street, you may not have the patience to do all that math. To explain it very simply: keep heavier car components as close to your car's center of gravity as possible in order to lower your car's polar moment issues. A mid-engined car will have a fairly low polar moment, assuming it isn't towing an elephant.***
25 Car Terms You Need To KnowPolar Moment of Inertia
To simply put it polar moment of inertia is "car's resistance to turning". Who wouldn't want less of that? No one would have bothered to go mid-engine design if reducing polar moment of inertia is not better for handling. On the other hand even the ultimate ICE mid-engine layout still can not reach what the skidpad layout could do in terms of both CoG and PMoI.
The example you gave may be because some drivers don't like the lighter steering effort and reduced road feel came with lower polar moment (less resistance of turning) of the adjustment made. Those can certainly be adjusted with suspension and steering tuning to take advantage of the low polar moment. When you got the physics right to begin with engineering work is much easier to follow. A lot of people have reported the Model 3 has probably the best steering response among all with similar weight without sacrificing too much on ride quality as other performance cars do. That's even that the Model 3 was designed as a family sporty sedan with range and comfort in mind and not an all out performance car. I have no doubt we will be surprised by how capable the Roadster will be in handling, with or without the SpaceX package.