Helen Keller was motivated to become an activist for the disabled due to her personal experiences with deafness and blindness. Having overcome immense challenges with the help of her teacher, Anne Sullivan, Keller recognized the importance of education and advocacy in empowering those with disabilities. Her desire to educate others about the capabilities of disabled individuals drove her to speak out against inequality and fight for rights. Keller’s activism extended to multiple causes, including women's suffrage and labor rights, illustrating her commitment to social justice and equality for all marginalized groups.