Human being or not, its living. Killing is killing and there's no excuse for that. Period.
And yes, its wrong to kill bees and spiders. Had you been taught otherwise since your childhood, or there were laws protecting the right to life of these "parasites" you won't be here using them as an example. Trust me.
Its just that its not possible to make and enforce laws to ensure the right to life's safety of every damn living thing out there. Its a perilous mistake if you think that they deserve anything less than you as far as the right to life is concerned.
Those are exceptional cases, you're talking about. I can speak for everyone else you quoted along with me, that we didn't speak what we spoke in that context.
Also, probably you have never met a rape-victim. Most I've met, would rather keep the baby. A mother's instinct, in most cases, is more overwhelming than "seeing the rapist's face in your own child".
Lastly,
Likewise. Besides, "respecting someone's life" is not enough to justify "killing a life". How can you even compare those two? Like I said, killing is killing. Putting on the "mah life mah rulez" mask ain't gonna help.