>To invoke Goodwin's Law, perhaps we should be more sympathetic to the viewpoints of Nazis? How about white supremacists?

Honestly, I would argue yes (with a big asterisk on your word choice of sympathetic). You need to engage with people and discuss their views in order to change them. Most people when attacked will double down on their views. If you can engage with those people, present evidence, and change their opinions then you are doing something meaningful to remove a piece of hate from the world.