What are the reasons why Plato's Republic considers the poet's two major crimes?

Plato made two accusations against the poet in the Republic. First, poetry cannot teach people to know the truth. For example, when a painter paints a bed, he just imitates the bed made by a carpenter, and the carpenter imitates the bed because of the bed. Therefore, literature and art are just "imitation", "shadowy" and "separated from truth by two layers". Secondly, poetry nourishes feelings, desires and other "despicable parts of human nature" that should be suppressed by reason. Moreover, Greek poets wrote all kinds of evils about gods and heroes, which destroyed religious beliefs and played an immoral role. According to these two major crimes, he expelled the poet from his utopia. But Plato doesn't actually deny literature and art, he just opposes literature and art with democratic tendencies. Starting from the reactionary aristocratic interests, he put forward the view that literature and art must serve aristocratic politics.

Because Plato believes that poetry does not produce rationality and science, but is the product of irrational infatuation. Because poetry is imaginary and fictional, it can't be regarded as history and science, and it hinders rationality. Imitation is the main reason why Plato accused poets. He said that imitation is a humble child born to humble parents. Plato criticized the poet's imitation art as sharing a bed with gods, carpenters and painters, and criticized the painting imitation art for being far away from real works and rationality, and not for the purpose of health and rationality.

Plato thinks poets are useless. Of course, they can't make beds, make chews and reins like craftsmen and coppersmith, help patients recover, direct wars and govern polis.

Extension:

Plato is the ancestor of western objective idealism philosophy. He regards "Shili" or the principles and principles of the universe as primary and eternal, while the world of sensory contact is a copy or phantom of Shili's world, which has no eternity and universality, so it is not only secondary, but also unreal. Plato opposes taking love as the satisfaction of interests and lust, and thinks that love is the admiration of seeing the beauty noumenon from the beautiful body in the world, and people can achieve eternal beauty through this love. Although this kind of thought has the significance of opposing vulgar love, it is essentially the view of spiritual aristocrat and a part of his idealistic system. The "platonic spiritual love" of later generations comes from his love theory.

Plato (about 427 BC-347 BC) was born in Athens and taught for 40 years. Ancient Greek philosopher, one of the greatest philosophers and thinkers in western philosophy and even the whole western culture, he, Socrates, the teacher, and Aristotle, the student, are also called the three great philosophers in ancient Greece. He wrote a lot in his life, and his philosophical thoughts were mainly concentrated in the Republic and Law.