Morning Scepticism: Tone

While it's all well and good to have a dialogue conducted in a respectful tone, why should a lack of one detract from the argument? Surely it's the argument that's important, and that can be presented irrespective of tone. Imagine if biologists responded to creationists "I'd love to tell you how the eye evolved, but I'm not going to say anything until you stop linking evolution with the holocaust." While it's a perfectly legitimate complaint about tone, it's not showing anything other than the absence of a case.