A general question that can be applied to specific situations.
Sometimes it's really one or the other.
So just assume that in this discussion.
And what is "humanity?"
People love to go on and on about "humanity" as if to be human is to be this glorious beacon of enlightenment and civility... and, well, if your poop stinks, then that's just inhuman.
It's just as human to become aroused by the feeling of someone's neck snapping in your grip as it is to cry at the sight of a child being re-united with his fluffy little puppy.
We are a predatory social animal - which means our concepts of territory spill over into our personal relationships. We claim the people around us as ours (or recognize them as being claimed by others). In times of conflict and stress - those who are not 'ours' will experience the predatory side of our nature far more readily than those who are our own.
Whether or not you consider this to be a good thing depends upon how superior you believe yourself to be to the world around you.
I believe this clip more or less puts it into perspective:
[video=youtube;0WURzIiEuD8]https://www.youtube.com/watch?v=0WURzIiEuD8[/video]