Final answer:
Augusto Boal is considered an inspirational theatre practitioner because he developed Theatre of the Oppressed, a form of theatre that empowers marginalized populations and encourages audience participation.
Step-by-step explanation:
Augusto Boal is regarded as one of the most inspirational theatre practitioners of his day because he developed a revolutionary form of theatre called Theatre of the Oppressed. Boal's work focused on engaging marginalized populations and empowering them through theatre. He believed that traditional theatre was oppressive and created a new form of theatre that encouraged audience participation and dialogue, making the spectators active participants in the performance. Boal's methods and theories continue to be influential in applied theatre practice today.