Tang Ju had to enumerate due to the complex and diverse nature of Chinese society, which necessitated a detailed and systematic approach to record and manage information. Enumeration, in this context, refers to the process of collecting and organizing data about individuals, households, and communities for various purposes, such as census-taking, resource allocation, and policy-making.

The reasons for Tang Ju's enumeration are multifaceted. Firstly, China's vast population and geographic diversity require comprehensive data to ensure equitable distribution of resources and services. According to the World Bank, China has the largest population in the world, with over 1.4 billion people as of 2021. This population size necessitates a detailed enumeration process to accurately capture demographic and socio-economic information.

Secondly, the Chinese government has historically used enumeration for administrative and policy purposes. For instance, the Population and Housing Census, conducted every ten years, provides crucial data for planning and implementing social and economic policies. The 2020 census, for example, aimed to gather information on population distribution, household composition, and housing conditions across the country.

Moreover, enumeration helps in identifying and addressing social and economic disparities. By collecting data on income, education, and employment, the government can identify areas in need of targeted interventions. For instance, the National Bureau of Statistics of China reported that in 2019, the urban-rural income gap was still significant, with rural residents earning only about 34.8% of urban residents' income.

Additionally, enumeration plays a vital role in disaster management and emergency response. Accurate data on population distribution and housing conditions can help authorities in planning evacuation routes, distributing relief supplies, and ensuring the safety of citizens during emergencies.

In conclusion, Tang Ju had to enumerate due to the complex and diverse nature of Chinese society, the need for comprehensive data for resource allocation and policy-making, and the historical use of enumeration for administrative and policy purposes. The vast population, geographic diversity, and the importance of addressing social and economic disparities further underscore the necessity of enumeration in China.