First of all, the overall style of The Book of Songs is idealized and comfortable, which makes people feel relaxed, happy and slow, which is completely different from the ruling thought of the Qin Dynasty at that time. At that time, the Qin dynasty wanted great reform, great achievements, great efforts and a brand-new look. Therefore, Qin Xiaogong thought that the existence of The Book of Songs would definitely affect the development of the Qin Dynasty, so he listed it as a banned book.
Secondly, Qin Xiaogong advocated political reform. At that time, Qin people had a unique bloodiness. Qin Xiaogong wants to train his people to be "tigers and wolves", but there are too many things about love between men and women and Yingying Yanyan in The Book of Songs, so Qin Xiaogong doesn't want his people to read such books. He believes that this will lead people to lose their fighting spirit, indulge in a slow-paced comfortable life, and change their initial ideological cognition.
Therefore, some people think that the Book of Songs was banned by Qin Xiaogong, which was a great loss for the Qin people at that time. Others said that The Book of Songs was really not suitable for the Qin Dynasty at that time, which was not conducive to the development of the Qin Dynasty. So, there is nothing right or wrong, it depends on which angle you understand it.