Tennis is borderline nationalistic. The reason why people have a hard time with Novak is cause he does not fit in to their establishment. Tennis is in the same league was polo, golf and equestarian as being country club sports. Country club is ususally reserved for certain people who fit in a certain clique. Tennis for a long time has been a borderline elitist, prejudical sport. Tennis has come a long way since then, but their elitism is still there espcially among elite management and marketers. Federer is an incarnation of what they want every tennis player should be like, he has classical game, he is often very steady and he hails from a country that is neutral and never had wars. Eastern Europeans always had difficulty in crossing over to the western standards. Western Europeans have always looked at Eastern Europeans as "others" or " different".
But I think Novak unlikability is highly exxagerated, he is well liked but the problem is that he is battling a hypermarketing machine with Roger Federer. Federer always gets the best of everything, that includes, sponsors, promotion, networking opportunities, and also better people behind him. They still want to continue the hype that Federer is the best ever even though he dominated during the weakest era of men's tennis. I don't know who Novak's agent is but they are marketing him the wrong way, he is not meant to be like a Federer he can become his own niche. He appeals to more alpha males with his physical out of this world fitness and machine like mentality.