Answer:
The author chose to include this excerpt to lay emphasis on the traditional belief of the society as well as the women in particular.
Explanation:
The one act play "King Arthur's Socks" by Floyd Dell is about how one single man had taken over the fancy of different women in the story. Lancelot had been seen to be involved with the women in the play.
The excerpt provided in the question shows the scene where Lancelot had came over to visit Guenevere who was darning her husband's socks. The mutual attraction and the eventual kissing scene shows how Lancelot can easily have his way with women. But later she exclaims that she's a;ready married, which led to their decision to forget about their attractions to one another.
The inclusion of this scene seems to be that the author wants to emphasize on the traditional beliefs of Guenevere about her status as a married woman in love with another man.