Your concern about people wishing ill on Castro makes it seem like you are concerned about him, especially when you bring up this imagined good that he could have done with his life:
You may be trying to argue that every life is valuable and has the potential for good, but it comes across as very dismissive of his actual actions. Your argument that he could have done something useful if he did not have “secret places to hide people” is also rather offensive. It seems very similar to the victim-blaming that victims of sexual assault deal with. For all we know, he could have done something useful if only those women had never gotten into his car …
I disagree. First of all, people in prison can continue to torment their victims, so it is wrong to say that he was “harmless” in prison. Secondly, I have every right to feel passionately about the subject of rape … which means that I have every right to get upset about what he did and every right to feel angry. One in three American women will be sexually assaulted in their lifetime. Why should we be dispassionate about the people who commit these crimes?
I know this may come as a surprise to you, but if I were in their position, I would be fairly upset to hear someone arguing that Castro could have saved the world if only he did not have places to hide people.