I buy a lot of groceries at Walmart. Very often, even if they have 25 registers, only a few are open. If I stand in line for half an hour with a cart full of groceries, putting up with whining brats wanting candy to old ladies counting out pennies to pay the bill, and the check out person happens to be a Muslim and won't ring up my bacon, I would pitch a very loud fit! They damn well do it or let me have it for free.
But I know and like Walmart (except for the few open registers!). I don't believe what you reported is actually true. Do you have a link?
You need to consider a better timing strategery (time of day, day of week, day of month), I suspect that there are shorter waiting times in there somewhere.