^Hey for all we know they're nothing more than farming equipment meant for bio-forming new worlds. The race that created them could be billions of years ahead of us and as such even their most innocuous technology could be horrendously dangerous in human hands. They might view planetary biospheres the same way we view a tiny colony of micro-organisms growing on some damp rock.
Actually, a thought occurs to me; if they are weapons, what if they're the *least* of this race's arsenal? Like their equivalent of .22 rounds? If that's the case what would their *serious* hardware look like? I mean I wouldn't want to stumble across their equivalent to thermonuclear warheads.