why did the us not want to be involved in Latin America in the early 1900s

Whether or not the U.S. wanted to become involved in Latin America is up for debate. Regardless, the U.S. did become involved in Latin America during the early 1900s, first through “dollar diplomacy” and later by military force.
During the Taft administration (1909-1913), the U.S. initiated a policy called “dollar diplomacy” in Latin America. This policy allowed American bankers and businessmen to invest in failing governments and businesses in Latin America. As a result, many Americans had a vested interest in Latin America because that is where they had invested large amounts of their money. Investing in unstable governments and businesses naturally led to losses of money and tension for many, and the U.S. committed troops to many Latin American countries in order to protect its financial assets.
For example, America had given the Nicaraguan government private loans in order to bolster that nation’s economy and treasury. In 1912, marines were sent to Nicaragua in order to put down riots and rebellions against the government (which the U.S. government had invested in and wanted to keep in place). U.S. soldiers remained in Nicaragua until 1925, were withdrawn, were recommitted in 1926, and were finally withdrawn in 1933. Similar occurrences happened in numerous Latin American countries, including: Haiti, the Dominican Republic, Guatemala, and Honduras. Taft’s successor, Woodrow Wilson, faced criticism for committing more troops to Latin American nations than Taft had.
The United States wanted to become involved in Latin America, at least in a financial sense. However, that involvement quickly escalated to the point where the U.S. had to commit troops to the area in order to protect its financial interests.