Assuming there is a free market everywhere this is true. However China does not have anything close to a free market, electricity is heavily subsidized and free

Assuming there is a free market everywhere this is true. However China does not have anything close to a free market, electricity is heavily subsidized and freedom to invest and run businesses is heavily restricted which can easily cause market failures such as this. The key takeway from the article is that for Chinese miners specifically there is still a large profit to be made, which indicates something screwy with the market in China.