User blog comment:BlouseGirl/Hate on Frozen/@comment-174.65.12.92-20140729220723/@comment-11133912-20140730124925

If a Hans was really a good prince, he would've held a trial for Elsa, not declare that she was going to be executed once Anna was locked up. Instead, after locking Anna up against her will, he lied to the Duke and declared Elsa to be executed, no arguments made. The fact that he lied about Anna's death is enough to put him as the antagonist. Think of it this way. What if someone did something that looked wrong, but there was no proof to back it up. So, he was sent to court, and instead of the judge hearing him out, he sent him immediately to execution. That wouldn't be fair, right? Same with Elsa and Hans. It looked like Elsa abandoned her people, but she was really trying to protect them, like she did with Anna; when they were younger, Elsa shut Anna out because she was afraid of hurting her sister again.

If you looked at Elsa's motivation for leaving her people, it's clear that Elsa is the protagonist, and when you look at Hans' actions, it's clear that he is the antagonist.