One of the very few ways I was similar to regular kids is that I perceived adults as being much older than they actually were. (While often perceiving them accurately as mendacious incompetents at the same time.)
For instance, in a movie I liked at the time and have since re-watched, a major character at the time seemed about 50-60 to me and in my view as a child was on the very doorstep of death.
Watching the movie now, I realize he is 28 or perhaps 30.
I remember very well what it was to be a child. How it felt, at least, and that I was really no different than I am now. Why do so many adults forget this, and then treat children and young people as if they are not people?
Perhaps it is because I was a very precocious child and grew up quickly that I have not forgotten the disdain and dismissal that I received from adults.
Perhaps also that people just like passing on the negative experiences they themselves experienced. Seems a common human thing to do.