The fact that racism or nationalism or any other sort of "we vs. they" where 
we are superior has existed in all mankind certainly argues that we are 
hard-wired to do that sort of thing. All groups of people, nations or tribes 
teach their children to hate others competing for the same space. But, to my 
mind, that does not change the fact that "You have to be carefully taught." 
Your parents and grandparents have to teach you your culture, must train you 
who to hate. We have shown in the United States in the past 50 years that 
nations can change their culture.

Nazi Germany went from the most despised nation in the world to one of the 
most respected in a matter of a few decades.

Fifty years ago you could have argued that aversion to gays was hard wired. 
Somehow a significant portion of our population has changed that through 
cultural change.
Paul