Voter registration rolls are pretty notorious for being out of date and unreliable.
Personally I don’t have a problem with anyone who wants to vote by mail being able to request a ballot. Most states already allow no-excuse absentee ballets.
I think the problem arises when the State automatically mails ballots to every registered voter at an address.
If too many ballots show up at a house because someone requested it, there’s a paper trail. If too many ballots show up at a house automatically, there’s zero paper trail to be able to tell if they were all filled out and mailed back, besides the overall voter participation rate going up, which surely it will do.