Why is human trafficking appealing to pimps and gangs?

The answer is simple, the risk is relatively low and the profit margins are high. Human trafficking is a lucrative business due to a demand for sex, labor, and organs within the United States and International community. Unlike weapon trafficking or narcotics, which are sold once, humans are sold multiple times (often in one day), increasing profit margin for the stakeholders. Pimps and gangs have recognized the demand for these "products" and are supplying the market.