Controversial Characters

So, we're reading The Merchant of Venice for my Shakespeare class, and there are some controversial issues with a character named Shylock. 

To a modern audience, he starts off sympathetic. He's an antagonist, but only because a protagonist, Antonio, has been a jerk to him for basically no reason. Towards the middle of the play, however, he starts to enact revenge, and he seems to cross a line there. 

In Shakespeare's time, he was considered a villain, so the actor playing him would have emphasized his villainy, whereas to modern audience, he doesn't seem villainous at all, at least not at first, so a modern actor might tone down his villainy, and perhaps even make him the unofficial hero of the play. 

My take on it is that neither Shylock nor Antonio are fully villainous nor fully heroic. Actors can minimize or emphasize certain points to tip the scales, but I'd say that they're both human. Antonio shouldn't have been such a jerk to Shylock, and Shylock shouldn't try to kill Antonio. Their nationalities and religions have nothing to do with it. 

I'm interested in (and a little worried about) seeing how the play ends and hopefully seeing multiple different productions of it, so I can get multiple different takes on these characters. But ultimately, I'd say that it's important to judge people by their actions, not pre-judge them by their demographics or by what role they play in the story. 

Not all protagonists are paragons, and not all antagonists are villains. Most characters, and all people, fall somewhere in between.