There's lots of crazy people in the world, not just in China.
A few years ago I was walking home from the shops when I saw this nice looking young lady running around on the park. I didn't think anything of it and didn't say anything. A minute later this lady runs up to and stops in front of me and screams at me.
My heart jumped and I stopped and said excuse me. She ran around me several times yelling something about the grass and her pony and then she left. There were no horses there and we figure she had just missed her medication that day.
More recently a guy threatened to kill me because I took a picture of his caravan that was parked on the footpath. I had to walk on the road to get past it and figured I would take a picture. The guy comes running down his driveway threatening to smash my head in with a piece of wood simply because I photographed his caravan. He went absolutely nuts. I ignored him and continued walking, and listening in case he came after me. He did run after me for about 20 metres and then stopped.
I called the council on him and had him done for parking on a footpath
I should have reported him to the cops but didn't. I still might.
So there are plenty of nuts on the planet, not just in China, but everywhere you go.