They're not.
When I was in charge of elections, returned Absentee Ballots were carefully scrutinized and verified (or not). This willy-nilly spamming citizens with unsolicited mail-back ballots is a travesty. It creates a free-for-all to facilitate cheating.
People need to get their lazy asses to their correct polling places on Election Day, stand in line (without whining) if necessary, and vote. Only truly disabled and people working overseas, including military, should be requesting Absentee Ballots.
Something I learned that’s disturbing is that often Absentee Ballots are not opened and are set aside. Supposedly, they’re only counted later on if the quantity of them could change the outcome of a race. Convenient policy if someone wants to mess with an outcome. (Traditionally, Absentee Ballots are heavy with views from the military which tend to be more conservative.) They all should be counted, no matter what.