There was an interesting article written by Gerry Adams (or maybe he was quoted in it) a few years ago when there was quite a high profile spate of racist attacks and there was an element of glee amongst some Republicans that they could use it to point the finger at Loyalism. He actually made a good point that Republicans shouldn't be so quick to point the finger because at the time, while is was true that most racially motivated attacks took place in Loyalist areas, it wasn't actually all that surprising considering that the bulk of immigrants lived in Loyalist areas. I'm not sure how much the demographics have changed since then but it would be interesting to see if there was any corresponding increase in attacks.
I'll see if I can find the article again.