A kidney is not the same as a fetus. Maybe a better analogy might work. But for a fetus as a kidney id say...if your kidney is malfunctioning get rid of it. But if u have a child and it is not harming a woman and risking her life on a level equiv to kidney failure...then this breaks down logically. This is especially true if the woman is pregnant due to her own indescretions...
Killing is killing. Sometimes there is a rational reason for it. Most the time...there isnt.
The type of organ is not the point of the analogy. The logic is stressing the dependence.
I, as a living human with rights, cannot attach myself to you in order to survive. I can't force that on you. I can't force you to take care of me and keep me alive via your body. Yes, I will die without you supporting me biologically.
If you refused to let me use your body, would you consider that killing?
If you refused to let me use your body, could the government step in and force you to allow me to use it to keep myself alive?
In the same way, a fetus, which is not a separate legal entity, cannot force itself on a mother in order to survive. It can't force that on a mother for 9 months (and neither can the government.) And yes, the fetus will die without the support biologically.
So, it sounds like you are more pro-consequence and pro-punishment than you are pro-rights.
When you have an itch and scratch your arm, you will get dead skin cells and living skin cells. Do you consider it killing when you scratch away 100s of living cells?