The administration grades the schools on attendance.

Our school does not count excused absences against you. obviously their/your MMV

Technically, it's still a fucked up metric, but if they don't curb it at the school level, it's a lot harder to do it at the state/parent level.

Parents have a pretty strong incentive to keep kids home rather than pay for daycare/neighbors/family to help. They're using the kids to wage the war.