Murdering someone is generally thought of as unethical and illegal, but many instances of hurtful speech, or even what some would consider hate speech, have been protected as free speech.
I feel this comes down to the question would you kill Hitler if you could stop everything he did? And ethics come into play because murder is bad, but would you commit one to save the lives of thousands? How about hundreds? tens? one or two? it gets complicated because what is ethical to one person might not be to the next.