Why was liberation theology so popular in latin america in the 1960s?

In the 1960s, Liberation theology was popular in Latin America because it has returned the control of the Church to poor from upper class where Christianity offered as a tool for a better society and self-improvement. This is resulted in drastic change of relations in between Church and State also Church and people.

An Ordinance for the Government of the Territory of the United States, North-West of the River Ohio, 1787. ... Considered one of the most important legislative acts of the Confederation Congress, the Northwest Ordinance also protected civil liberties and outlawed slavery in the new territories.