The ACLU is wrong to defend nazi rallies because tolerating intolerance in the pursuit of tolerance is misguided and just leads to more intolerance. We don't need nazi rallies for people to be exposed to nazi ideology, we have the holocaust museum and other educational settings where people can learn about that without a bunch of hatemongers publicly displaying threats against other people.
Would you support someone's right to promote child sexual abuse, as long as it is words? What about direct threats to individuals? Are you cool with someone threatening your life as long as they just used words?