Number one, all I know about Hitler, I learned from history books and television/movies. I've never known him personally (I'm not old enough to know him personally.). Never knowing him automatically tells me that I cannot like or dislike (love or hate) him.
Number two, I can hate what a person does without actually hating the person. Example: I hate that my sister abused her kids and lost custody of all but one of them to her ex-husband (The one she didn't lose custody of isn't his child.). I still love my sister. In fact, I love my sister enough to tell her that what she's done to her kids is wrong. By the way, I can forgive my sister for what she's done to my nephews and my niece because I know them and love them. My anger for what she's done to them could affect my every day life.
In other words, if I knew Adolf Hitler personally, I could still hate what he did/does without actually hating him. :doh:
What if there was a connection between your ex-husband and Hitler?