WE are bio-weapons?

This was an idea from an old fan-fic of mine, but given the "revelation" hinted at by Idris Elba, I've considered it again; could the big reveal be that Humanity was originally created as bio-weapons (how many species have we endangered or wiped out? how many of each other have we decimated?), but got out of hand, attacked our creators, and the aliens were created to protect the Space Jockeys/Engineers from US? Humanity was exiled to a backwater planet (Earth), which had been created to breed the ultimate bio-weapon. Perhaps the Engineers feel that we only have two modes - killing, and reproducing so we can kill again, (remind you of a certain Gigeresque something? :P) and fear that the Human "infestation" has spread this far from Earth, so prepare to return and wipe out our homeworld...by contrast, Shaw feels that despite our nature and initial programming, Humanity has many elements which emerged without the Engineers influence (love, art, beauty, compassion, science, philosophy, culture ETC), which make us worthy of existence. This "creations becoming more than their original programming" could also play out on a microcosmic level with David the android striving to be accepted by a human crew...? I don't know, just a thought...(although this may be too close to the "Mankind sucks" approach of Avatar...:P