You're taking this example out of history? These days people don't see baptism as that important. You would have to believe the baptism was magical to feel you need to wash it off.
When one undergoes Christian baptism it is important to understand why it is a requirement in the first place. What does it mean? What is baptism and who can be baptized? Is it a complete immersion or just a sprinkling of water? What is required of a person afterwards?
The baptism that Jews undertook in Jesus' day was a first for them. They were born into a dedicated nation and did not require baptism into the faith. John the Baptist began the process as a means for repentant Jews to publicly demonstrate, by undergoing complete water immersion, that they had repented of their past sins and were ready to accept and follow their coming Messiah.
When Jesus came to the Jordan River to be baptized, John declined because he knew that Jesus had no sins from which to repent, but Jesus told him that this one time, was OK because Jesus' baptism represented something else. His immersion under the water was a symbolic "death" to his former life and being raised up to a new life of dedicated service to God in a new capacity. From that day onward until his death, Jesus lived the selfless life of a humble teacher. Jesus' followers were required to undergo John's baptism in preparation for accepting Jesus as Messiah...and once they had accepted him, they had to undergo another baptism "in Jesus name" to become "Christians".
When Gentiles came into the Christian arrangement, they did not have to undergo John's baptism because they were not under Jewish law, but were baptized as followers of Jesus Christ.
Baptism is a public demonstration of one's commitment to living a Christian life based on the teachings of Jesus as God's representative on earth.
It is similar to the vow taken in marriage, before witnesses, not to be entered into lightly and understanding what it means to take a vow of that seriousness and then treat it with contempt.
If one has undergone baptism under false pretenses then God would not have viewed it as valid to start with.
To be baptized as a follower of Jesus Christ requires commitment because it was not going to be an easy course. (John 15:18-21; Matthew 7:13-14) Genuine love of God and appreciation for the sacrifice made by his son on our behalf, is a vital part of our dedication.
To turn your back on that dedication and turn to living a life alienated from Christ will bring severe retribution from God.
Ecclesiastes 5:4-6..
."When you vow a vow to God, do not delay paying it, for he has no pleasure in fools. Pay what you vow. 5 It is better that you should not vow than that you should vow and not pay. 6 Let not your mouth lead you into sin, and do not say before the messenger that it was a mistake. Why should God be angry at your voice and destroy the work of your hands?" (ESV)
Defectors and rebels have no future in God's plans.