Does anyone believe that if the situation were the other way
around that Ranma would care at all? 

Sadly, yes.

Ranma has already demonstrated that he's a traditionalist in several
areas. Look at his "I don't fight girls" bit, for example. I can see him
looking down on Burakumin easily.

	Yeah, that's a possibility, however with his life being an extensive 
training trip there's a question of just how reflexive the Burakumin/uncelan 
knee jerk reaction is in Ranma.

   I like to think that he would say "I don't care what your pgrandparents
did. I love you." I like to think that's what Akane would say, too. But
you never can tell.

	If you want an american counterpoint read The Adventures of Huckleberry 
Finn.  Huck was raised in the pre-civil war south, where the beleif that slavery 
war a good thing was as all pervasive as Japan's attitude toward the Burakumin. 
 Now in the course of the story he got to know Jim the runaway slave, and became 
friends with him even though he "knew" that helping a slave escape was a truly 
bad thing to do.  By the end of the story he had reached a point where he was 
preparing to tell Jim's former master where he was, but instead he decided to 
free Jim and help him escape.  The important thing is that even after he made 
this decision HE STILL CONSIDERED SLAVERY TO BE INHERANTLY MORAL.  He didn't 
decide that a system that could enslave Jim was bad, he decided that because he 
was friends with Jim HE would turn his back on everything that was right and 
help him.  Attitudes take a long time to change.