Because the main idea of this poem is: because you are in Lushan Mountain, your vision is limited by the peaks and valleys of Lushan Mountain. What you see is only one peak, one ridge, one mountain and one valley, which is only partial, and it must be one-sided. This is what you see when you visit the mountains, and it is often the same when you observe things in the world.
These two poems are rich in connotation, which enlightens us to understand a philosophy of dealing with people-because people are in different positions and have different starting points, their understanding of objective things is inevitably one-sided; To understand the truth and the whole picture, we must go beyond the narrow scope and get rid of subjective prejudice.