*Could* have been?

So, I’ve been listening to Rihanna’s song Man Down, which I quite like, but there’s one line that drives me absolutely crazy:

‘Cause I didn’t mean to hurt him
Could’ve been somebody’s son
And I took his heart when
I pulled out that gun

*Could* have been somebody’s son? *Could* have? Is it possible that he wasn’t somebody son? What, did he spring from the foam on the ocean? Erupt from a volcano? Materialize out of thin air? Why the hell would anyone write such a line? Did no one at any point in the production of this song point out “Um, yeah, that doesn’t make any sense.”?