So this is the direct cause of Wu Dalang's death. In fact, this is not the only cause of death. What caused Wu Dalang's death was the poison of Pan Jinlian and the boss.
Besides, is there any reason for Wu Dalang's death? Yes! Because Wu Dalang is weak, short, short, flawed in appearance and stupid, he will feel unworthy of Pan Jinlian himself. Before Pan Jinlian poisoned him, his unusual behavior did not attract his attention, and he did not realize that Pan Jinlian wanted to kill himself. Therefore, Wu Dalang has its reasons in this respect. To put it bluntly, he is stupid.
There are also social reasons. Without Ximen Qing's intervention, Wu Dalang would not have died, which means that the social atmosphere at that time led to Wu Dalang's death. If the society at that time hated, criticized or denied this incest and adultery, the vulgar atmosphere at that time was not prevalent, or the social atmosphere at that time was better, Wu Dalang would not have died, and Pan Jinlian would not have thought of hooking up with Ximen Qing. Then if the atmosphere of a society is good enough, these people will not be influenced by this bad vulgar concept.