Oh wow. It definitely sounds like your mom was giving your behavior a pass. And how could she not when she was the one who taught you racism. We are sponges to our parents. "Out of the mouths of babes," often

manifests from the teachings of the adults around us.

And that your stepfather knew it was wrong and weakly offered you insight into his different opinions from your mother.

Love that your teacher's response made all the difference. What you wrote on your school paper sounds like what kids do when there is an inner struggle between what the world is teaching them and what they know in their heart. Perhaps subconsciously, you wanted your teacher to "call you out" on the drawing to help you find your way back to your heart.