You are right! A baby shouldn't be murdered. Thankfully we have murder charges for people who kill babies.

Unfortunately, I don't think you know what a baby is. A baby comes after a viable fetus comes out of the womb, until that point it is just called a fetus.

I'm going to give you a very simple analogy: Let's say you ordered a new Tesla. You put in your order and wait a bit and your order is finally ready. You are delivered your brand new half a car! If I call it a car then it's a car right?