Art is something different to everyone because for some people it can describe feelings and for others it can be something that makes your house look good and to make you feel happy.
There are different types of art because some people want to explain feelings and others want to feel happy. If all art was the same then the art people decorate their houses with would all look the same.
Artists also make different art because everyone wants different types of art like arts and crafts and other things. If people want a canvas with painting and lots of decorations like paper and pop up butterflies, then they won't get what they want to decorate their house if all art was the same.
Humans also create different art because everyone wants different types of art because everyone thinks different and everyone likes different things.
That is why there are different types of art.