Ignoring whether it was the Nine Provinces or the modern era, many people wouldn't treat a matter like death casually because they felt that it signified being unlucky. There was no need to mention kings.
Look at the emperors and kings of the ancient era. Which of them hadn't tried to exhaust all efforts to search for a way to prolong their longevity?
Sun Mo's words could be said to be extremely rude and in grave breach of societal norms.
Xiao Luqi was over 50+ years old, and no one had ever spoken to him like this before. Hence, a green vein on his forehead throbbed violently, as though it was on the verge of an explosion.
If Sun Mo were a eunuch, he would be beaten to death right away before the emperor thought about anything else. However, Sun Mo was a glorious great teacher and was also a valued guest of Song Yan. Xiao Luqi truly couldn't do anything to him.