Hmmm I'd like to point out something: like many other traits, whether compassion and emotional warmth are seen as strengths or weaknesses, depends on the society and culture, and era you belong to. In certain parts of Asia, the men are emotionally detached to the point of being utterly cold. These men likely have no compassion, no empathy and it is seen as a strength. To show emotions is seen as a sign of weakness like crying when disowning their children or feeling bad for beating some sense into their wife. (This manner of behaviour was probably also true for certain classes and types of females.)
Of course, in the modern 21st century Western society, this behaviour is probably seen as an aberration and thus, a weakness, because humans are supposed to be expressive, kind, caring, nurturing and stuff. I say "modern" since I recall reading in various sources that during Victorian-era and prior, the way people treated one another was really different. It was perfectly legal to execute children for stealing bread, to beat your wife and so on, depending on the "era" you were in. Humans just don't change so quickly. After all, we are still a highly vicious and violent race and no matter how much we convince ourselves that "we're nice and civilized" using theology, philosophy and so on, the memories of violence still remain within us on a certain level of our subconsciousness.
And yes, I agree that to a certain extent a conscience is formed by social construction--but not entirely. There is much evidence (for example see the work of Steven Pinker) that certain human emotions are universal across time and culture. Compassion certainly is one of these--the Buddha taught it 2500 years ago. How that compassion is expressed may look different in different cultures or different eras. For example, if there is an Asian male preference for keeping a stiff upper lip as in Victorian England, that does not mean that those men lack compassion. You would have to look into their minds to know that.
I don’t really know how much humans have or have not changed over the millennia. I can say that I believe, as Doug intimates, that love and compassion have existed as enduring human traits right alongside hatred and violence. That seems to be how it is for us, for now. And as to what we are in our essence, a "vicious race" as you put it, well objectively speaking that remains to be seen, doesn't it? I have a different view of humanity based on my own explorations and insights. Humans can behave violently, obviously. They can also behave kindly, which to my mind is equally obvious. However, beyond the duality of yin and yang, black and white, good and evil, love and hate, compassion and violence, male and female and so on, there is a perfect order and infinite intelligence that manifests as all that we see and experience. This view allows me to see humanity in a much kinder light. But I am not arguing that you should believe me or take on my point of view. I'm just sharing what works well for me in helping me to lead a life that I can love.
By the way, thank you crazy dice and Doug from Vermont for your very kind words and your insightful comments. It's great to see that we're all trying to do the best we can, trying to figure this thing called life out so that we can love ourselves and others well!