If Humans Don't Embrace Each Other Why..

Human being do not embrace one another - in particular when it comes to different races, humans have not in their past nor now, holistically as a united species, reached a point where they feel connected to other humans, regardless of skin color or physical and cultural differences.

I have had this notion in my mind that if we were to discover intelligent life forms such as ourselves outside of our planet, that both we and the other alien species would embrace each other - that we would in essence feel as though we are family in this huge cosmic fugue. That it would be an immensely spiritual and happy occasion to have found other entities that belong to the universe just as we do.

But it is occurring to me now that this notion and the sentiments that I have regarding it is perhaps not how humans and other non-Earthly life forms would react. Because if humans don't demonstrate kinship towards other humans, what expectation is there for kinship to extend beyond the human race? I imagine early human explorers during the days when the globe had not been explored. And how after sailing across oceans and upon discovering new lands inhabited by foreign races, so much blood was shed over territorial possession. How instead of being fascinated and delighted at discovering new races of humans, people treated each other with cruelty. And how centuries later into the current era there are still wars and world peace is just something people like to dabble about.

If our own species is so divided and have shown a sever inability to be family with one another, why is there any reason to believe that if we encountered a new life form outside of Earth, even if they were highly similar to us, that there would be unity between us and them?

What reason is there to believe that if another planet exists, just like Earth, with intelligent beings, just like humans, that upon discovering each other there would be some cosmic harmony and peace between us and them, simply because we had found each other? What reason is there to believe that there would be happiness, rather than dissension as has been exhibited between humans?