Children for the most part are innocent and there is so much they simply do not know. A lot of people/children experience bullying and they don't know what to do when it happens. It's about power, as a matter of fact all primates do it. We tend to remember bullies too, not because we are weak but more so because being bullied frightens and confuses us and often when young we simply don't know how to react to it so we tend to cower and feel fear.

I am sorry that you have been challenged with depression, that can happen when someone feels powerless too often and thinks poorly of themselves for how they feel and can't seem to pull out of it. Inside you there is talent though, and that's what you need to discover.