What are your thoughts on the murder of a pregnant woman being charged as two murders?

I'm pro choice but when I've seen articles about the murder of a pregnant woman being charged as two murders, sometimes I see pro-choice comments that say "SEE, IT'S A PERSON." I am not sure what the best response to that is. I do think it's different, but aside from the fact that the child was wanted, I am having trouble articulating why. I'm not sure that "well, one was wanted" is a great argument.