Yeah, people who fight for weak are not seen in good light. Even if you are from a weak community you shall be hailed if you do the bidding of your betters, even there limits are there as to how much you can rise, everyone wants to see you do good, just not better than them, thats the world we live in.
In the real world I feel Novak was disliked in the beginning because he came across as confident and outspoken, remember when he beat Fed at Montreal 07 then he said Roger you cannot win all the tourneys, you have to leave something for us as well. This sort of statement would not have gone down well with Roger who has a massive ego. On the other hand if you see Nadal, right from 04-05 Nadal had a very intimidating body language on the tennis court, but after the Match Nadal is soft spoken, shy and does not do any taunting or anything, so this must also have helped Nadal's image build up when he was new. He was beating Fed at Miami and still he was looking humble off the courts.
Federer was extremely intimidating on the court because he was far more talented than anyone and he is an extrovert as well, so he is outspoken even outside the court. In his prev gen nobody was as good as him, even Agassi was humbled by Roger and in his gen he crushed everyone who was dominant before him (Safin & Hewitt), so Fed was absolute Alpha
In Nadal's case he was extremely intimidating on clay, not quite so on other turfs as Fed was still ruling there, so Nadal compensated that by being very bumble

Fed probably didn't mind that and liked Rafa.
Novak arrives and he is confident of his abilities, Fed is pissed off, he probably thought "This punk is of Rafa's gen and Rafa has achieved so much more than this punk and Rafa is respectful towards me, why is this fellow so much outspoken and confident before even winning ?? "
So you see, this might have soured their relations ...... That's my guesss
Am I right
@pj80 @Hitman or is there any more theory to this rivalry on how Fed and Novak started disliking each other right from 2006 itself while same Nadal despite his intimidating presence of clay was like by Federer as early as 05 ???