"...Picking on the weak is wrong, and you don't get to take advantage of a fellow human because you're physically or mentally able to do so."
You are kidding right? Survival of the fittest is the only rule in life. Just look around. People who were smart enough to "make" the most money or physically brutal enough to steal the most are your owners.
When someone has that kind of power by whatever means, and uses it to make your life miserable, you have to take them out when it is clear your "society" is not going to help you.
Even kids know this, and some of them actually attempt it.
The truth is that we are still apes with a haircut and shinier, smarter ways to kill each other.....same as it was when all had was a rock.
Survival of the fittest describes the ability to reproduce, not dominate those around you. Indeed, if it referred to the ability of an organism to dominate all around it, it would eventually run out of resources and die. Not very fit.
You are correct that might makes right. But we are different from the apes in that we have a choice. We can choose the kind of world we want to live in and work towards realizing it. Just because the powerful keep making the same selfish choices doesn't mean it has to be that way. We make it that way.
There is still a lot of pain, fear and ignorance to be worked through in the world. We are improving in that many of us recognize that the patterns of domination are not good for us. We at least recognize that it's not what we want. But we still go with selfish impulses, so clearly we have a way to go yet.