How does mama explain mr simms behavior to Cassie in roll of thunder chapter 7?

Mama explains Mr. Simms' behavior to Cassie by attributing it to the oppressive system of racism that they live under. She explains that white men like Mr. Simms feel threatened by educated and ambitious Black boys like TJ, fearing that they might challenge the white power structure. The white community uses tactics like lynching and other forms of violence to maintain their dominance and keep Black people suppressed. Mama stresses the importance of education as a means of fighting back against this system and gaining equality. By understanding the context and causes of Mr. Simms' behavior, Cassie develops a deeper understanding of the racial injustice prevalent in their society and becomes more determined to overcome these obstacles.