Which is a central idea of gates’s mister jefferson and the trials of phillis wheatley?

I'm pretty sure, that the main idea concentrates on the racial discrimination and stereotypes of American society in XVIII century. The story is about a black woman named Phillis Wheatley, that was kidnapped in Africa and sold on the market as a slave to the American loyal family. But besides her chores she had an opportunity to study and get more intelligent, so she wrote poems which have become popular. This book is aimed to show the struggle of the black people that are being humiliated by those who treats them as nothing, the black people who can disprove Thomas Jefferson's words : "Blacks are inferior to the whites in the endowments of both of body and mind", and prove that they are not savages.