People are pretty lenient about killing each other as it is.
Killing has never bothered humanity in the slightest.
That is a huge generalization and is largely inaccurate.
So who did the crusades bother?
When Rome conquered most of the known world at the time who bemoaned the deaths?
Who denounced the Colosseum other than those that were at risk to be thrown into it?
Murder does not bother humanity. At most it scares some individuals. It may be a generalization but it is generally true.
A murderer gets the electric chair. Does it bother you? No. Why? Because you aren't a murderer so you have nothing to fear from it.
My point is, murder doesn't bother us, the fear that it could happen to us scares us. Since we all are developed past the age of a fetus there is no risk in allowing abortion.
One final question, you turn on the news and see a murder. It's not especially horrific, just the run of the mill gang shootings. Does it disturb you in any way? Do you even notice it as more than a passing fact?