And the thief on the cross proves that it doesn't.
Some Protestants may not be familiar with these two kinds of Baptism:
Baptism of Desire — someone on their deathbed
Baptism of Blood — typical of martyrs.
The Good Thief experienced both of these.
All the thief on the cross proves is that Jesus could cleanse that man of his sins. What Jesus did for the thief he did not do for us. He took the thief’s sins away before He died. Everyone coming after the cross must come into contact with the blood of Christ Jesus through baptism.