Understanding "The Man with the Blue Guitar" by Wallace Stevens [closed]

Here is the first part of the poem:

The man bent over his guitar,
A shearsman of sorts. The day was green.

They said, "You have a blue guitar,
You do not play things as they are."

The man replied, "Things as they are 
Are changed upon the blue guitar."

And they said then, "But play, you must,
A tune beyond us, yet ourselves,

A tune upon the blue guitar
Of things exactly as they are."

I'm trying to understand the last sentence

And they said then, "But play, you must,
A tune beyond us, yet ourselves,

A tune upon the blue guitar
Of things exactly as they are.

A tune beyond us, yet ourselves, -- what does it mean?

To the first part, about how the melody sounds are different with a blue guitar, the artist replies that when he plays on the blue guitar not sounds are different but things are different which the melody is about.

But I quite can't grasp the meaning of the reply from the crowd.

You do not play things as they are. Accusing him of making things up or embellishing them. Rather he tells the truth in an entertaining way.

Things as they are, [they] Are changed upon the blue guitar. His excuse is that the guitar gives him the liberty to extemporize/exaggerate.

They are demanding/insisting he do what he has told them he cannot do.

But play, you must, A tune beyond us, yet ourselves, Of things exactly as they are.

To play a tune that is beyond them, beyond their experience yet that reflects their experience. It must still be true, exactly as things are, as well.

I think he is up to it.