Agathon here takes “imitation of an act”* as far at it can go.
Euripides and his relative Mnesilochus are off to ask help from another existing tragic poet; Agathon, Agathon is rolled out on an eccyclema, lying spread on a divan, dressed very fashionably in women’s clothes and begins composing a choral ode for a female chorus- to be posted.
All the while there are jokes about his effeminacy and the subject of his passive homosexuality. However, the actual joke might not be the feminine manners of this poet-that’s just the garnish. Maybe, the joke is on how far actors and poets would go in order to better portray their roles- you will remember the story of the actor Πώλος (late 4rth century) who played Electra and allegedly put his deceased son’s ashes in the jar containing by narrative Orestes’ ashes in order to better emulate Electra’s grief.
What’s important here is that the behaviour of women and its imitation in drama by men was a subject that really occupied both actors’ and playwrights’ minds. One of the most important aspects a woman’s life in the ancient greek world that is usually downplayed is their involvement with lyrical composition. Women did have their dances and songs that portrayed their world from their point of view. Their work was also known to their male colleagues.
Female creativity was neither unknown, nor shunned and the corpus of women’s work not only appeared in anthologies compiled by male poets, but also appeared in historical accounts by men. Unfortunately the greatest part of it was destroyed and erased in subsequent times, coinciding with the rise of christianity and its prosecution of such female practices, which were tied to the practice of religion as well.
(You can see some of the surviving poetesses and their poetry here)
When Agathon first appears, Mnesilochus compares him with Cyrene; a hetaera. It should be noted that hetaeras were always very well musically educated and have been immortalized as well as intelligent conversationalists. The same goes for less prestigious female companions, the majority of them if not acrobats and dancers, were musicians.
It is not a stretch of imagination to consider that playwrights could seek the company of such female artists for “professional” reasons as well, especially if said playwrights were already on the “feminine” side. We will see more men on the feminine side both literally and figuratively later in the play, which you can read here.
Take note however that the concepts presented in Aristoteles’ Poetics are indicative of his time’s dramatic practices. The concept of imitating nature is a pretty big chapter of ancient thought and at times it even encopasses the distortion of reality to better approach truth. Female presence in comedy and tragedy is also subject to such distortions.