Well
About forty years ago, I was hired as a stockboy at a department store (remember those?) over Christmas break from school. On the Friday after Christmas, I was not surprised to find my name on the assignment sheet for the following week, only amused that I hadn't heard otherwise. More than sixty years ago, my father, then employed by a federal agency, moonlighted at the United States Post Office (if you remember that) about Christmas time.
So whatever Amazon may have invented, seasonal jobs aren't on the list. None of this is to excuse ill-treatment of its employees. The troubling aspect is that 1960s and 1970s jobs for teenagers--seasonal stockboy, MacDonald's cook--have come to be the least bad or only option for so many grownups. A discussion of that would be most interesting, but maybe not up The Register's alley, as a) involving a lot of companies with less computing involvement than Amazon and b) too dreary to be perked up with snark.