I call what you describe above selectionist belief.
You really do have to be able to acknowledge that by saving the ladybug you are in part the cause of the further deaths that it goes on to commit.
You know that it will do it. But because the ladybug is cute, you choose to save it.
An aphid is not cute... you choose to not acknowledge your part in that bit of the puzzle.
Out of sight out of mind.
I do not understand this.
I save things all the time.
Snakes, lizards, bugs.
But I acknowledge that I just played a part in that snake going out into my yard and eating/killing the other residents there. A toad, a lizard, etc.
If I had allowed nature to take the natural course it was already taking the other thing would have a better chance.
I am impacting the living of another being by choosing to help this one.
Affecting the life of this animal is causing the deaths of many others.
To not accept that is naive above all things.