They're not supervillains, why do they need an origin story? It tiny-fying.
I'll agree to that, but with their over use as a major threat they became "big bad of the week". This has made many speculate on their origins and the authors found that the best way to end them was to give them a beginning.
They were especially space-zombie-like there, and it was pretty cool.
Again I don't dispute this, but if you are going to use something as a threat (and they were suppossed to be a major threat) you have to expand on who and what they are.
"Star Trekkin' across the universe, On the Starship Enterprise, Under Captain Kirk.
Star Trekkin' across the universe, Boldly going forward 'cause we can't find reverse."
Star Trekkin' by The Firm.