According to Grendel, what is the truth about poetry?

One night Grendel watches an old blind man and his assistant entertain the people of meadhall. The man is a shaper, and through music and poetry, regales Hrothgar and the others with an especially fabricated account of Danish history. Grendel is perplexed. He knows the truth of Dane history is quite the opposite from the shaper's account. Yet Grendel finds himself drawn to the prose and music of this bard. Grendel feels a paradox. Even in the lies of the poetry, there is truth. The truth of art and poetry enchants and enrages Grendel.