This plays in with why they require new JWs to get baptized even though that person may have already been baptized. They don't recognize baptism as being between the individual and God. Rather, it is a contract between the individual and the corporation.
Then they turn around and contradict themselves with this little nugget.
w72 2/15 Living a Dedicated Life p. 121
Regardless of how you are actually living your life, God, who accepted your sincere request at the time you were baptized, views you as responsible to stand by the declaration of faith you have made. Jesus said: “Just let your word Yes mean Yes, your No, No.”—Matt. 5:37.