Compare that to an Amazon fulfillment center, where from what I've seen they walk a lot to pick packages (but even that's being automated away by Kiva robots), put the contents into boxes, and load the boxes into trailers. Amazon packages are relatively light compared to most business shipments of stuff that went through UPS (which are usually things packed in bulk). Maybe it's mind-numbing, but the horror stories about how physically grueling it is (save for maybe when they weren't properly air conditioning the facilities) seem overboard. Even then, there were days in the summer where I'd be unloading a trailer that was baking in the sun all day, and we didn't get AC in there -- we just sweated it out and drank a lot of water.
I don't really know what people expect when they work in a warehouse. It's not glamorous and it's not easy, and it doesn't require that much skill so it doesn't command that much pay. But it's better than no job at all.