Using a hash table as auxiliary storage is a perfectly reasonable 'sorting algorithm'. He's not asking you to name one of the common sorting algorithms. He's asking you to solve a sorting problem, with a loosening of the usual limited memory constraint.

Once you've scanned the list, why do you have to traverse the 100 lists at all (unless you want to further sort them on 'name')? You just need to merge all the lists (In the mom case, simple concatenate all the stacks). This is a constant time operation.

The 'trick' here is to think about how would you implement a sort if you had no memory constraints. As the blogger rightly says, engineers will usually pick one of the standard ones without thinking (I would surely do the same).