For voters deleted from rolls during SIR, why Form 6 remedy raises questions

People who have never voted generally fill Form 6 to enter the electoral rolls. Why is it being invoked for those whose names were dropped during SIR?When voters whose names were deleted from electoral rolls during the Special Intensive Revision (SIR) process are asked to apply afresh for reinstatement, can they be required to declare that they are first-time voters?