I don't know what Puzo's intent was.

If it was to simply take a shot at black folks, then fuck him...but it doesn't negate the pleasure I get from reading the book ( I read it at least once a year.)

If his intent was to show the mindset of immigrant criminals then he did a good job.

I truly don't know and I can't criticize Puzo or Coppola b/c it was their piece of work, and again I don't think that specific line is the point of the story.