"Sure, there have been many atrocities throughout history; but how many were averted because someone took initiative to make the world better?"

I don't know, but I'll start you off with an example. Dropping two atomic bombs in Japan in August 1945 ended World War II, stopped the almost maniacal conquest of Asia by fascist, militarist Imperial Japan, and saved millions of Japanese children who were being trained to fight American tanks with bamboo spears, all of which made the world better. Of course there was a price for that as well, just like for everything.

"I believe our capacity for love runs deeper than our capacity for self-interest/survival/greed..."

I take it that you have never been divorced. Once you find out how fickle love is, you may change your mind about that. Anyone who says they love everybody is full of crap. They don't know everybody.