Identical product under numerous ASIN’s

Is it permissible under Amazon’s terms for a seller to create hundreds of different (presumably standalone) ASIN’s for the identical product, no variations, and separate product listing for each ASIN?

I thought ASIN’s were supposed to be like UPC’s and always be the same for products that are the same.

I see this often, on a smaller scale, and don’t understand why it’s done. And can’t fathom any reason for doing it on a large scale like that. Is there some legitimate reason a seller may choose to do that?