Why does the US government plan to build a wall along its border with Mexico?

On the surface, the United States is doing this to combat smuggling, drugs and transnational crime. But in fact, the purpose of the United States is to force apartheid.

In recent years, because of the imbalance of internal affairs, the economic situation in the United States is not satisfactory, and the separatist tendency has become increasingly prominent. Especially in the southwest near Mexico. Since several states in this region were originally Mexican territories, they were occupied by the United States after the US-Mexico War. Therefore, in the context of the overall poor internal environment in the United States, a large number of Mexicans in this region have set off a "relapsing fever." In order to prevent this situation from worsening, the US government intends to build a "separation wall" on the US-Mexico border.

PS: This move by the United States was opposed by many Latin American countries, including Mexico. The Mexican president even directly accused the United States of doing so as a "shameful" move.