Because the word "your surname" has been widely used in ancient times, it can't be changed when it spreads to modern times. If it is forcibly changed to say that your surname is not nice, it is a bit evasive. Moreover, feudal superstition has existed in our country since ancient times, including now. Building a house and getting married depends on the date and counting the eight characters, not to mention the fact that it is related to one's name, because some places of the surname can be said to be dead, which is unlucky.
Chinese culture is extensive and profound, and there are many uses and meanings between words. For example, in ancient times, surnames were separated, and besides, there were names, characters and numbers. But we don't think modern people are so troublesome. Generally, they have two or three or four names, and most of the time they have a nickname at most. Surname+first name makes up a person's name. This number is a nickname at best, not even a nickname.
By the time of Qin and Han Dynasties, the two words of surname had been combined, and the surname meant what your surname was. Later, the names were also combined, and it was not used until the modern number. People call each other more and more succinctly.
Besides, the homonym of the word "Shi" is death, which has a bad meaning. Let's imagine that two people we don't know have just met, and one of them says you are your surname, which sounds very strange. Everyone just uses different words on different occasions. For example, some villages or towns are generally people with the same surname, and they all have a genealogy. Generally speaking, they say X's genealogy, and they don't say X's genealogy. It seems that the ancients also understood that words are not smooth.