I can't understand why some people love to hate tennis players. Not just Fed - any player. I can't understand what people get out of it.
How you see Fed, how I see him, or how his fans see him, those are personal opinions and interpretations based on his public image. We can't judge his actual personality because all we know is his public image.
Whether you admire or despise it, well, that's your choice and your opinion. But I don't think these things should be treated like facts or like matters of life and death. After all, it's just tennis.
It's the football approach, I guess. Love Liverpool and hate Manchester United - or vice versa. Love Barcelona and hate Real Madrid - or vice versa. You seldom see the most engaged fans liking both. Plenty of hate going on there. Probably not that surprising it spreads to individual sport, with some deciding not only who their favourite is, but also their arch-enemy.