Most of the time hating an opponent is just rationalizing your own shortcomings by projecting them onto the opponent. I play competitive tennis and I badly want to destroy my opponents, but I certainly don't hate them in fact I socialize with a lot of them.
The only things that would cause me to dislike an opponent is if they did something unethical like cheating. Fans should follow the lead of the players and coaches in team sports. Play your a$$ off when the games on, when it's over, shake hands and go home. If you won, be happy, if you lost, then don't blame the opponent, find out what you did wrong or where you can improve, increase your practice, develop new skills - always try to get better. When the games on it's the only thing in the world that matters but in the end, remember it's just a game.