In my opinion, Shylok is a villain because he matches the definition of what a villain really is. A villain in someone or something that causes harm or damage. He is causing Antonio harm because he plans on punishing Antonio for not being able to pay off his debt to Shylok. He is the one responsible for harming Antonio, therefore giving him a reason to be called a villain. Although in some contradicting opinions, one might say that since Shylok is discriminated agasint, he should be considered the victim rather than the villain. However, in this situation, just because Shylok is Jewish, it does not stop him from being characterized as a villain in the play.