Eh, people hold grudges for anything. You can get yourself hated for winning too much, losing too much, speaking your mind too much, and pretty much anything else imaginable. It almost seems like people purposely try to start beef with other people, especially online.
And then there is the league experience, where you have really good decks, and people grow accustomed to losing to your deck, and thus don't want to play you in the future. Not really hate, but more of a technique to avoid playing you.