Final answer:
Joe does not want Janie to talk with the people on the porch because he believes such interactions are beneath her status as the mayor's wife and would tarnish his image of respectability.
Step-by-step explanation:
In Their Eyes Were Watching God, Joe Starks (also known as Jody), who is Janie's husband and the mayor of Eatonville, does not want Janie to interact with the people on the porch because he feels that her engaging in their conversations and socializing with the townspeople is below her station as his wife and the mayor's wife. Joe is obsessed with his image and status in the community, and he sees Janie as a symbol of his success and a reflection of his own image. By keeping her separated from the townsfolk, particularly from participating in the lively and often crude banter that takes place on the porch, he attempts to maintain a certain social order and control over Janie, while protecting his image of respectability.