Baptism symbolizes Jesus’ death and resurrection. One who gets baptized displays their decision to follow Jesus to the church. (Mark 1:9; Acts 22:16)
Those who have decided to follow Jesus should be obedient in baptism. Jesus was baptized and commanded His followers to do the same. (Matthew 28:19; Acts 2:41)
You do not need to be baptized again if you have already accepted Jesus and been baptized by immersion. However, if you have been sprinkled or baptized before accepting Jesus, then the next step is baptism.
We don't take this stance to devalue the mode of baptism practiced by other denominations, we are simply trying to be obedient to what we feel the bible says about being baptized.