The difference between hacking and destroying

Hacking has gained a reputation for the destruction of things when in a actual fact it is the idea of obtaining a higher knowledge. I know that sound like illuminati propaganda but here is an example. Some one does a SQL injection attack on a site to gain knowledge and someone who does a denial of service attack destroys a site, nothing was gained the only thing that occurred was the destruction of a site. In my personal opinion I find no reason to destroy things but it depends on what if you want to learn or destroy and in that tone please send me a email if there is something you want to learn destruction wise or educationally I don't encourage the act of destruction but I feel it better to teach things to others no matter what they can do with it.