Ignorant people irritate me

Ok, as per my previous entry, I don't do abortion debates anymore. What I do participate in is correcting people's dangerous though processes.
If you want to be pro-abortion, fine. I don't agree with you, but I'm not going to go over the finer points of biology with you or argue ethical stances. My entire career is biology and ethics and I just don't feel like getting down in the mud with you and wrestling over it. I have actual lives to go save, thanks.
What I can't stand, what I can't let go, is when people try to justify their stance by trying to define human life with standards of intelligence or being self-sufficient or physical capability.
Why? Because doing so ranks every human being on a continuum of more human to less human. And from that we get genocide. We get the holocaust, we get Rwanda, we get slavery, we get women getting acid dumped on them for daring to go to school.
Why can't we just narrow everything down to DNA? If you have individual distinct human DNA, you're a human. Plant DNA = plant. Crab DNA = crab. Treponema pallidum DNA = the syphilis bacteria.
For instance, one such person on ReveLife said:
"I would say yes a fetus is less human than I am. I can survive outside my mothers womb, I can breathe on my own, I live off nutrients that I feed to myself not that are fed to me through a tube. I don't share blood with my mother. I'm free to roam the world as I wish too, and have a fully developed brain."
Can't anyone other than me see the danger of such generalizations?
As I explained in my reply: "Ok, so say a four year old (or a 16 year old, your brain isn’t fully developed until the prefrontal cortex is finished, well into adulthood) is in the hospital, restricted to bed rest and unable to roam. They’re on a respirator, with a G-tube giving them nutrients, and several blood transfusions after an accident. They’re expected to recover in the next couple weeks. This is a very common scenario. Are they less human than you and me? Should I quit busting my butt and just let them die?"

Now, I'm not saying this person thinks my 4/16 year old isn't human. Or is less human. But they made a generalization that allows for that to be extrapolated.
And people may think that I'm extreme, or silly for thinking that we could wind up a society that thinks that way. Fine, whatever, chances are good we won't be around for either of us to be proven right. But you look at the things we, as a global society, allow to continue or justify and you know we didn't get here overnight. It happens little by little as we chip away at our consciences.
Or as we make rash generalizations all in a futile attempt to make ourselves look right.

WHY THE HECK DOES ANYONE CARE WHAT PEOPLE THINK OF THEM??? Hmm?? If you're pro-abortion why do you go around trying to justify it? You should just be able to say, "Well, I'm right and it's legal so I don't need to explain it to anyone else." If you're anti-abortion you should be able to say "Well, I'm right and if they don't get it by now they never will."
Both sides have heard all the arguments and both sides think the other side is retarded.
And. It. Will. Never. Change.

Fight a battle you can win, people. Instead of continuing to say things that sound like you'd love to unplug a 4/16 year old fighting for their life or that you think sperm and eggs are people too.

(Oh, and if you use medical evidence to back up your point, make sure you know what the heck you're talking about. If I have to correct one more person on genetic disorders that are easily googled...)