In my view, the remarks made by the Chinese diplomat in Japan were misinterpreted. He did not intend to threaten to “cut off the head” of Japanese PM Sanae Takaichi. What he meant was a warning: if a war breaks out across the Taiwan Straits and Japan sticks its head into it, that head will be cut off. I believe the essence of his message was not wrong.
The truly malicious one is PM Takaichi herself. Two former Japanese prime ministers have criticized her for implying that Japan might get involved in a conflict in the Taiwan Straits. She is crossing a red line.