L.C.
I think what makes something hateful depends on two things.
1. Delivery. If someone says, "I disagree because...." that's just a difference of opinion and isn't hateful, just different. Then, if feelings are hurt it's the fault of the hurt party. If someone says, "Are you serious??? How could you possibly think that.....? That's just stupid." Well, now that's hateful. It isn't about a difference of opinion, it's about making someone else feel small for thinking differently. The hurt feelings are the fault of the other party.
2. Content. Any kind of prejudice or slanderous comment against any group of people based on how they look, what they believe, who they love, where they live. Basically, anything that attacks at the WORTH of another person based on these things. We can believe someone is wrong in their choice, we can't make them feel less than. That's hateful. Any statement made solely to hurt or harm another is hateful.