User blog comment:Saraphael02/7 and more mysteries of One Piece/@comment-5387880-20130217120827/@comment-6540043-20130217124732

Yes, that was how Oda want us to show the discrimination between Chopper's fate and those people and still a mystery on how Chopper's nose turned to blue. xD It was maybe one of the effects of Devil Fruit that Chopper ate or maybe a curse or disease.