...Now a humanism worthy of the name could of course not be concerned solely with a part of human nature, but would have to be concerned with the whole of human nature, including its beast of prey part. Any 'humanism' that seeks to conquer part of human nature for the sake of another part is by that token already transhumanism. A humanism worthy of the name must be a superhumanism, in the Nietzschean sense: concerning itself with the full human being, including its terrifying and questionable aspects.
It is precisely our "humanism" which is most destructive of humanity--destructive of its natural high points. But to actively combat that movement would itself be an initiative to conquer human nature: for the herd animal part is as essential a part of human nature as the beast of prey part is; and its only natural for the former to wish to abolish the latter...
In the context of our current world, overpopulated and consisting mostly of what you refer to as the herd, the "beast of prey" part of human nature is rather dysfunctional. We don't need to hunt other creatures in order to survive and thrive.
Who said anything about hunting other creatures? From what you say about our current world, it's rather an obvious conclusion that the beasts of prey among men should thin out the herd a bit... Or would that also be "dysfunctional"?
So I think that suppressing "the beast of prey" is not a particular matter to be opposed to. It is a part of our DNA and even if suppressed extraordinarily, it will arise (and still, dysfunctionally, does) as context demands.
You fail to address the threat of transhumanism. And I think the suppression of the beast of prey part is the most sensible thing to be opposed to (which is not to say that it's completely sensible). For the natural high points of humanity, the great philosophers, fully partake of it.
The threat(?) of trans-humanism? Are humans going to genetically modify themselves to, in a fashion, somehow completely lose their more base animalistic instincts? Or are we going to replace ourselves with benign (or otherwise) self sentient robots?
Uh, I guess it's possible, (especially in science fiction) but throughout our history the evidence has been, and continues to be, that what will, actually, most likely, happen is that humans will continue to have a tremendous capacity for acting inhumanely to other humans.
As far as culling the herd, it should not be necessary for some humans to kill other humans to address over-population, although, no doubt, humans will continue to kill other humans throughout the foreseeable future.