Because minorities are too stupid to know how to vote and mail a letter, and must count on other people to come by, fill in their ballot, and carry it en-mass to the election board? Yup, zero chance to fraud with that process!
The last 50+ years have been about removing any sense of responsibility from certain minorities to provide a steady stream of clients for the nanny state.
The strategy has served the state well; the citizens, not so much...