@xris,
It would be foolish and irrational to prohibit killing, all inclusively.
Everyone kills.
Whether our immune system is killing a virus or a bacteria, we inhale little floating critters and our system kills them, step on an ants, swat a mosquito, yank a carrot from the ground (or a cow) to eat, etc...
To prohibit killing in general is absurd and impossible, a fool's task.
Context demands that the bible commandment refers to murdering (legal term) humans. It's 'god' actually commands to kill, multiplicitously, so inconsistencies in the book are plentiful, but the context of the commandment seems obvious, with a bit of thought.