Though unable to give a complete answer to them, we may show--first, that his views arose naturally out of the circumstances of his age; and secondly, we may elicit the truth as well as the error which is contained in them.
He is the enemy of the poets because poetry was declining in his own lifetime, and a theatrocracy, as he says in the Laws, had taken the place of an intellectual aristocracy.

Euripides exhibited the last phase of the tragic drama, and in him Plato saw the friend and apologist of tyrants, and the Sophist of tragedy.

The old comedy was almost extinct; the new had not yet arisen.

Dramatic and lyric poetry, like every other branch of Greek literature, was falling under the power of rhetoric.
There was no 'second or third' to Aeschylus and Sophocles in the generation which followed them.

Aristophanes, in one of his later comedies (Frogs), speaks of 'thousands of tragedy-making prattlers,' whose attempts at poetry he compares to the chirping of swallows; 'their garrulity went far beyond Euripides,'-- 'they appeared once upon the stage, and there was an end of them.' To a man of genius who had a real appreciation of the godlike Aeschylus and the noble and gentle Sophocles, though disagreeing with some parts of their 'theology' (Rep.), these 'minor poets' must have been contemptible and intolerable.
There is no feeling stronger in the dialogues of Plato than a sense of the decline and decay both in literature and in politics which marked his own age.