Please read the article again. See the bit that says "ME lived with many other humans (men and women); she was certainly not alone"?
ME and YcA are the matrilineal and patrilineal ancestor of all humans and all men respectively. That does not mean they ever met, or even lived at the same time. After all, your mother and paternal great grandfather may never have met, either.
No, sorry. Try reading for comprehension next time.
Very logical.
It is logical when you understand it.
When you don't, though, it's easier to just to ridicule things to cover your discomfort over your inability to grasp the material.