The problem is that people don't care.
A person who "knows" that human life begins at conception,could saute human embryos in a little butter and garlic and serve them on basmati rice.
It's generally (though admittedly not always) religion that gets them to the point of caring. It's a larger faith --- religious faith usually, though not always --- that gives them the doctrine, or just juices the intuitive hunch, that "human" is not totally like "animal, vegetable, or cybernetic."
It's sacred.
I do understand what you're saying about a secular approach. I did that for years.
What I have seen is that if people lose their all-in attachment to a religious scale of values, they'll get the "science" but they won't give a damn.
Exactly! That is the defining difference.