Why do people abuse?

The following sites will give you some insight as to why.

https://www.google.com/search?q=Why+do+people+abus...

They do because of how they were treated when young.

Yes, I sure think so. 'Like begets like', especially when one is a child. That is why it is so important to be a good person. Both good and evil have a way of spreading.  Many people who as adults are .. well... not the greatest people were mistreated. I have read that many pedophiles were victims of pedophilia. The Bible tells us that the Kingdom of Heaven is like Yeast. Yeast grows and grows, until everything is affected by it. It is VERY important to be a good person, if you want others to be good people too. Likewise it is very important NOT to mistreat others, if you don't want to be mistreated.

Because they are miserable and yes.