Most likely some Jap nationalist just bribed them to put the names there. Investigation would clear things up.
Regardless, as the tablets now exist, it's an opportunity to desecrate them, practice for the day when Chinese troops drag the dirty ashes from out of Japan's own war criminal shrines, regardless of Japan itself voluntarily surrenders them or if the Army seizes it by force. And making clear the stance of China against nazism, which I'm sure Korea would also appreciate.
Trash should be disposed of in such a way it doesn't damage the environment. In ww2, the Soviet Union had an excellent way of removing nazi insignias. Flags/symbols were put on a wooden platform by people wearing gloves, then the symbols together with the platform and the gloves were burned, so the ground would not be polluted by Nazism. This method can be used to dispose of Japanazi remains.
