I don't think that's the idea. You don't have to call any violence "good." But you might want to avoid being perfectly balanced: violence by Nazis is meant to intimidate millions of American citizens into silence; violence against Nazis is meant to intimidate a few hundred morons into silence. Neither kind of violence is good, morally or practically or legally speaking. But to suggest they're equally morally reprehensible is, well, laughable. If you can at least admit that, you should be able to have a conversation about race with your liberal niece or nephew.