Does anyone know that it's legal to remove people by head in Yonganzhou Town, Taizhou City, Jiangsu Province?

It must be illegal. There are too many similar situations. I suggest you consult a professional lawyer. I recommend Zhao Jian, a demolition lawyer in Beijing. He has taken over many cases in Taizhou and has been there many times, so he knows the local situation better. You can search his phone number online and then call for advice. He should give you a detailed answer. Good luck!