In this story, the parlor walls encourage a society in which people do not really care about one another. They also encourage a culture in which entertainment is superficial and does not include thought. These are the major problems with the society in which Montag lives.
The parlor walls encourage people to involve themselves in completely mindless shows instead of engaging with the outside world or even with their own humanity. The perfect example of this is Millie Montag. She is so addicted to the parlor walls that she does not really care about her husband. In addition, she has no interior life. She does not think about anything or feel any emotions. This is because she spends all her time with the "family" in the parlor walls.
The parlor walls, then, encourage an impersonal and anti-intellectual culture in Montag's society.