So is it or is it not inhumane and immoral to kill a powerless human in a most painful way?
A powerless human what? See, you're trying to use vagueness and imprecision to avoid the actual issue behind the disagreement over abortion.
You've already stated that it's a human fetus. And the answer to your question is that we don't know if it's "inhumane" or not to abort a human fetus, and at what stage in it's development. Or if it is "inhumane", that it matters, significantly. As it's equally "inhumane" to force a woman to carry a pregnancy to term against her will.
The problem here is that you don't recognize the difference between a human fetus; essentially, a parasite living inside an autonomous human being's body, and an autonomous human being, fully formed. But other people do recognize this difference, and so they ethically consider each of these phenomena, differently, as a result. You may not agree with them, but until you can better articulate your disagreement, and not try to hide it behind your own vague feelings and assertions, they have no obligation to pay your feelings and assertions much mind.
I'm certain nobody cares how intelligent I think I am, so I'm not going to waste keystrokes defending my intellect.
Nor will anyone appreciate what isn't there for them to experience. That's the thing about "not caring about what others think". It's an invitation for them not to care about what you think, in return.
I'm even more certain nobody cares how intelligent you think I am.
I was doing you the curtesy of explaining why your opinions are so easily dismissible. If you don't care about these shortcomings, then I don't care, either.
I don't care how intelligent you think you are either.
Or perhaps you dislike expressions of intelligence because they make you feel stupid, in relation. And you'd rather disparage the intelligence of others to make yourself feel better, than to learn from it. Which is, in fact, a stupid thing to do.
There are plenty of reasonably intelligent people who are immoral and wicked because they love darkness rather than light.
Yes, and you think of them every time you're confronted with an intelligent person. Because thinking of them disparages intelligence and makes you feel better about your own stupidity.
You are one of them, and nobody will care how smart you think you are in hell.
Intelligent people appreciate intelligence, and want to learn from it when they encounter it in others. Stupid people try to deny their own stupidity by disparaging the intelligence of others, when they encounter it, because it makes them aware of their own stupidity, and they don't like that.
Intelligence requires the courage to accept and admit to one's own intellectual shortcomings, and so learn from others. A lot of people lack that courage, and so remain imprisoned by their own ignorance.