Or maybe even recycled bins

from here and here (image source)

Don't get me wrong, repurposed malware isn't a terrible name for them, I just think think when you're dealing with attackers doing something seemingly clever, a little psyops are called for. "Hand-me-down" has more baggage than "repurposed" and that's a good thing in this context.

(The recycled bins comment in the title is perhaps a little more in keeping with the punny nature of the"What idiot called it" meme)