I have the same experience. I also overshot "assertive," but the alternative was that everyone would continue to steamroll me to the point of despair. Assertive wasn't enough to safeguard my dignity.

It is indeed exactly as you said. The world chewed me up for being innocent. I was routinely physically assaulted at school. These things were passed off as roughhousing or joking and the adults never intervened, and some even seemed to appreciate the "humor."

The adults rolled their eyes at me essentially for being weak, it was sort of like "sigh, what are we gonna do with that kid?" It occurs to me now that these were bitter, jaded people who hated a child for his naiveté.

If I defended myself, I was the bad guy. At some point I thought: "it doesn't make sense that I am the one who is right and that everyone else is wrong, so maybe I should be more like those guys." But then I got punished too. For example, it was considered funny for people to kick me in the balls at times. It had happened to me 10+ times and nobody got punished. Regrettably, I did it once to another kid and it was a scandal and I got punished.

I am in a healthy place now but I thank God I got through the teen and young adult years without becoming a criminal. I think I easily could have, because I came out of school a deeply damaged individual.