The main point that has been made over and over is that there are no ethical systems that make sense to derive from evolutionary theory.
The eugenics one is, in fact, counter to evolution when it is understood. We do NOT understand what to select on so it would be very stupid to start doing wholesale selection based on what would, in the long term, be potentially dangerous criteria. We DO know that diversity in the gene pool is a very good safty factor for a species so selection can be dangerous if it starts to reduce diversity.
The eugenics movement was, of course, attempting to draw on evolutionary principles. It was using a very poor understanding of the whole science however. It is just the kind of poor understanding that literalist fundies are promoting for all they are worth today.
There's no evidence for such an idea.
It may well be a leap. I'm not an expert. But for sure as heck you don't know if there is evidence or not. In this case it doesn't happen to matter if there is or not.
What there is evidence for is that we developed compassion long before there were any of the modern monotheistic religions about and there is some hint that we may have developed it before we actually reached a point of being human.
If people are naturally drawn to small tribal groups what's compassionate about engineering them against their inclination?
I suggest that we need to consider the idea that we do have inclinations that are not compassionate or what we might like to see us have from an ethical point of view. The inclination to kill and eat creatures for meat is considered by some to be very unethical. I don't think we need to argue that most of us are born with such an inclination. If we, as a society, decide that this is indeed unethical then we will have to learn to engineer away from it.
The fact that we are not a separate creation from those others may, in deed, allow us to reach such a new ethical viewpoint. Not something that the fundies have much basis for however.
(btw, in case it makes any difference, I am not a vegetarian, but I can understand how some may arrive at that ethical viewpoint)