Why do we mistreat and dehumanize others?

I believe that abortion is a sin .  I just have an issue with the murder of a child.  I just feel that anyone who practices abortion has blood on their hands.  It is another form of dehumanization just like what happened to blacks over 150 years ago and Jews over 65 years ago.  This is sick and so sad.  No one deserves to be misinterpreted.  As a matter of fact, I am watching a sermon on abortion and the 'preacher' mentioned Dredd Scott and what happened to the Jews in Europe.  It is sick how people can have that power to dehumanize another 'citizen of the world' just like how some people have this either in the United States that has happened to fellow citizens.  It makes me wonder how difficult it would be to bless a nation where groups of people have been and unfortunately will continued to be divided.  That is ungodly in of itself.  In my opinion, God, help us all.