Why always national parks mean place with lots of wilderness?

I mean why not national park is called animals' garden or habitat?Why always national parks mean place with lots of wilderness?
I think the Whitehouse is classed as a National Park. There are a lot of different National Parks.
the term national park was coined to indicate federal land set aside for conservation efforts to maintain wilderness areas for future generations. by the way the national park system has been adopted by nearly every country around the world since it was first instituted here in the US in the 1800's. there are other areas of the country that are listed as sanctuaries to prevent hunting of game animals. Why always national parks mean place with lots of wilderness?
I think animals like to live in national forests because there are no humans living there and no hunting.
That's funny. The nearest national park to me is in Philadelphia and contains such things as the Liberty Bell, Carpenters' Hall, and other buildings. Not much wilderness there.