Why would cars only be rented? Is it because I suggested that a gun range could rent guns to shoot? Again, cars are not built to be killing machines. They are built to transport goods and people. When a mistake happens, a car turns into a killing machine. The difference is that when a gun is properly used, its a killing machine and when a mistake happens, its still a killing machine.
See the difference?
As for sports cars(mass produced and sold at dealerships) specifically, yes they are built for speed, but more accurately they are built for acceleration. When used properly, a sports car is no more or less dangerous than a minivan even though it can accelerate faster. The faster acceleration is not more dangerous on its own.
Any car made in 2015 can reach speed limits and well beyond, whether its a sports car or not. They aren't built and in demand for top end speed, they are built and in demand because they express an attitude and feeling that appeals to some drivers. That does not make them inherently more dangerous.
To tie this back to guns since you want to keep trying to support the terrible example made by that other poster- a gun is made to destroy. a sports car is made to display a lifestyle and attitude that the owner wants. My high school girlfriend had a turbocharged Mitsubishi Eclipse Spyder. It was the ultimate teen girl car and accelerated absurdly quickly. It was not more inherently dangerous than my Ford Taurus as each was ultimately made to do the same thing- transport us. When properly used, each car safely transported people. Compare that to a gun which when properly used, destroys. See the difference?
The example that other poster made is bad, no matter how many clarifications are made to it.