What is a bad game? What is bad to you may not be bad to me and vice versa. Bad is a very subjective term. Whether bad or good, no games should be banned. Leave it up to the consumer to decide which games should be purchased. If consumers are not interested the purchases will reflect that and the games will quit being made in the future.
Some people argue that bad games cause violence and such but that is just nonsense. The reason that there is violence is because the people that commit them choose to do so, they know what they are doing and still do it. Also, parents are at fault for letting their kids see bad games because they do not listen to the age restriction on games and give their young child the game anyways.