Imagine a law that let one group decide whether another group counts as a person. That's what legal abortion does. From the moment of conception, there's a distinct, living human organism with its own DNA, not just a clump of tissue. It's dependent, sure, but newborns and the elderly are dependent too, and we don't treat that as a license to kill them.
The strongest pro-choice argument is bodily autonomy. I get it. No one should be forced to donate organs or blood. But pregnancy isn't the same as being hooked to a machine for someone else's benefit. It's a unique relationship where the natural course is growth and birth. A society that calls itself humane should protect the weaker party, not erase it for convenience. So no, abortion shouldn't be legal as a general right.