You said that non-stutterers who never had to worry about their speech don´t care about it. That is just false. 1) They do care. A lot of them. 2) They also struggle to speak. They get nervous, anxious. Some people don´t talk and appears as very silent. Some people talks excessively fast and incoherent. Other´s become umcomfortable and are shy away. It is important to distinguish this reality because our vision of the world affects our blocking behaviour. Such false belief will work side by side with stuttering. Be aware.