Strangers think they know better
Children need to feel safe in every situation. And we are there to protect them. Also, a child is not self-dependent and has no judgement until certain ages. Every parent knows better which are the needs and likes or dislikes of his child. He also knows everything about his moods and feelings.
Now, I'm telling you, STRANGER, why do you think you know my child better, or why do you even try to talk to my child when he's playing in the park, or in any other place? Why do you think your approach is better than mine, or your advices are good for me? Do I know you? Do you know me? Do you think your life experience makes you a better parent than I am? Every child is different, and education has different perspectives for everyone.