Missed the point
I feel that other commentators have missed the point, the union has suggested that the pickers fall under mail order and retail industries, where as Amazon calls them logistics workers.
If I order from a Next catalogue either on the internet, phone or by mail, we would refer to this as mail order, even if they use a logistics company to pick, pack and ship the item. If I order from the online Amazon catalogue then they call themselves a logistics company, I personally cannot see the difference.
The union, whether you like them or not says that Amazon is a mail order business, and therefore the workers need to be recognised as such, which may result in better pay and conditions. I wholeheartedly agree with them on one hand but remind them that Amazon can always open up warehouses elsewhere that can serve Germany just as well and probably cheaper.