Interesting question... though it would be more accurate to look at supercar accidents per thousand people to get relevant data.
1. Cars are status symbols in China in the way your home is a status symbol in Beverly Hills, CA
The first thing a wealthy Chinese business owner buys is a Ferrari.
The second thing is a Koenigsegg
Its part of their culture - as is being perceived as someone who doesnt care... notice how they all have that "dont give a sh** about anything" look in that picture on the highway? (also wtf, 10 cars and 6 people, are there 4 photographers???) This is their growing upper class, this is what they spend their money on, and this is the personality they like to convey to the world.
2. Simply put there are more people there... if there was an equal distribution of supercars all around the world, there would be equal distribution of supercar car accidents. But they have such a huge portion of the world population that they will thus also have a higher number of supercars there versus elsewhere in the world, and therefore more accidents as well
3. They are an extremely wealthy country, with over 3x the population as the US its to be expected that they have 3x the wealthy people. However given the current economic climates, its likely they have even more than the 3x figure that the population ratio would dictate. Their economy has been growing for a long time, and I can tell you if there is a WW3 it will more likely be economic based than anything else. China knows what it is doing and they are going full force into their plans.
So, if we do a really rough estimate and assume those 99% movement nutjobs are onto something, with 1 billion Chinese citizens, 1% of that population will be wealthy ...meaning there could be 10,000,000 (ten MILLION) very wealthy people in China! FWIW, following this rule, USA has three million.
Given this information, I would EXPECT there to be 3 supercar accidents in China for every 1 in the USA