It's not like that at every store. For example Winco makes you bag your own shit, and smaller grocery stores like Raley's and Safeway have these "courtesy clerks" which are pretty much dedicated baggers/helpers. Walmart is actually the only place I've been to I think where cashiers are normally expected to bag. Bagging isn't generally that bad though, it just kinda sucks when you get the customers with the $200+ totals and you get little to no help.