Many people may ask why there are people who do racing as a sport when they can do other kinds of sports. It is also the same reason why the race drivers ask others why they do that kind of sports. The motivation for people is different for each person. Then in your opinion, what is the motivating factor for the race car drivers to do the sports. that is what we will learn as it is the most motivation for most or all of the drivers.
This is the yearning for speed. Race car drivers have the common feeling of having the addiction or high for the speed that they can experience. When drivers are on the race track, they can just forget all the cheering, the reactions of the audience, and everything else except focusing on the race track so they could stay on it, prevent themselves from crashing, and be the winner of the race. They can be a completely different person as they give all their efforts and focus.
That is why many who have experienced it likes to do it more and more and so they are very happy to be on the race track and doing competitions. Sometimes it is not on winning but on the experience one can have. But racing on the race tracks with all the necessary safety measures including the gear of the rider is very different when you race on the public road. An accident is high to occur.