I would say that the main thing that makes nature special in this sense is that when you are in nature or contemplating nature, you can be confident that the resulting thoughts and feelings are uncontaminated by all of the (visible and invisible) ideas and biases and assumptions that are present in your particular time and place.

Uncontaminated by the wishes of my fellow humans, yes. Uncontaminated by eons of biases built in to my brain, no. I'm not sure why one is preferable to the other.