It was pushed by the DNR and hunting groups. The county opt out was the only way to get it passed because there were a few reps/senators around Rochester and Mankato who didn't want itAnd it was the legislature...not the DNR and certainly not hunting groups...that passed other legislation that allows counties to opt out of the repeal of shotgun only statute where that applied.
I would hold out hope that if your county opts out that will change eventually though....