I can understand disliking a character, as e all have or preferences. What I couldn't understand was the tremendous hatred and why there are so many haters. It's kinda ironic how they hate more and for less reasons that Sasuke himself.

These are some of the reasons I've seen, though most are just straight up stupid.
His personality. Apparently, Sasuke is emo, and people hate emo. He is arrogant, thinks he is better than everyone else, and they hate this, even though it is the truth and he doesn't think he is better than everyone, just Naruto. Then they hate because of his fanboys. Example, Sasuke and Naruto are pitted against each other, and then Naruto fanboys and Sasuke fanboys collide, and haters are born, with the poor few who just so happen to like them both, suffer.
Some people are jealous as ridiculous as it sounds. To some, Sasuke reminds them of someone they hate, or they secretly wish they could be like him. Or maybe they hate what he stands for and what his character is about.