This section on baptism is necessary because there are churches that teach that baptism is necessary for salvation. In other words, they state that without baptism you cannot be saved from the judgment of God--even if you trusted in Christ and receive him as your Savior.
When someone says that baptism is necessary for salvation, it logically means then there are no exceptions. If something is necessary, then it is an absolute requirement. For example, it is necessary for Christ to have died on the cross and shed his blood so that we could be saved. Without his atoning sacrifice, we cannot be saved. There are no exceptions. Jesus is the only way (John 14:6), and there are no exceptions. Likewise, when someone says that baptism is necessary, he must affirm that there are no exceptions--otherwise, baptism is not necessary. This would mean that anyone would trust in Christ, saying on his deathbed, and had received Christ by faith but were to die before being baptized, he would go to hell. This means that faith in Christ is not enough to save a person, but the person must perform a ritual in order to be saved. CARM stands against this error.
Baptism is important
Baptism is important, and every Christian should be baptized. We are in no way intending to diminish the importance of baptism. But it is not the thing that saves you (See 1 Pet. 3:21 regarding "Baptism now saves you"). Baptism is a covenant sign, a public declaration of a person's identification with Christ; and it symbolizes identification with his death, burial, and resurrection.
So, as you read through these articles on baptism, please understand that we are saved by grace through faith--not by grace through faith and something else. Justification is by faith in Christ Jesus--not by faith and water baptism.