Liberation Theology is to be found right in the Torah itself.
We do express a preferential option for the poor, and the Gra believed that wisdom resides among the poor.
Tehillim 37:11 says that the poor will inherit the earth, and Sukkah 29b says that among the 4 things for which someone’s property should be confiscated are gasut haruach and mistreatment of the poor, and the pasul from tehilim is there cited.
Immediately following this is a discussion of lulav hagazul.
This indicates that we hold ethics and social justice in high regard, right alongside ritual obligations.