Indeed, not "might". Things are immoral because they do produce bad consequences for others, de facto. Murder, rape, assault, theft (for simplicity).

The title was about us giving moral concern to it, as a life, to treat it as we treat other humans because it has the psychological dimension of life. The problem of not treating something morally when it deserves moral concern. It's not only about might hurt us back indeed ;) That is just a reason to consider recognizing moral concern for it by recognizing how it can reciprocate a reaping back onto us for what we sow, just like any human can that we harm. It's not the limits of why moral concern should be applied.

The taking of an innocent life "humanely" is fallacious self-deception. Humane from human treatment. We would put someone to death who did a crime with the least pain because we choose to. We would put someone to death for suffering cancer and pain because we choose to. But to take the life of an innocent who did no harm to us, did no crime, or one that is not already suffering to end it's continued suffering, is not humane. Saying you would prefer a quick painless death might be true, but you would also prefer not to have to be killed by another for their selfish reasons (not for crime done, not for ending prolonged suffering). Humane as "marked by tenderness, compassion, and a disposition to kindly treat others", is not applicable when you take the life of an innocent who did no harm or isn't currently suffering endlessly.

Moral action is anything that is not immoral action. Immoral actions cause harm (violating their will to not have things done to them) to others who did no harm, who are fine and healthy and don't want to have their lives ended. No justification on the part of the aggressor (eg. survival) changes the action being immoral. Moral applicability to actions only applies to causal agents that have a capacity to understand abstraction like the concept of morality and be responsible for their actions being moral or immoral.