It's not entirely accurate to say that the "sharpshooter battalions in the Confederate army had nothing to do with sniping and marksmanship."

It is true that their primary mission was conceived to be ranger-like light infantry "daring enterprises", and that they were more often described as skirmishers rather than sharpshooters, but it is clear from the general orders establishing and organizing the battalions that they were also to function as "sharpshooters". The list of qualifications for service in the battalions included "good rifle shots" and "skill as marksmen." Further, "ordnance officers will see that the sharpshooters are equipped with long range guns, and if possible, that the guns are of uniform caliber."

Finally, Union and Confederate accounts from the Vicksburg siege include several references to the accuracy and effect of the battalion's sharpshooters in a classical sniper role.

I see the Confederate sharpshooter battalions as something akin to modern ranger battalions -- elite, light infantry units, intended for small-unit operations, with every man qualified as an expert marksman.