Early on in my marriage, this attribute tended to get me into trouble from time to time. I remember saying to my wife, on at least a handful of occasions, "for right now, I want you to just listen to what I'm saying and ignore how I'm saying it". This seemed to be a nearly impossible task for her. At first, I found that exasperating; why couldn't she allow me to be a little rude sometimes, when I was angry, but still hear and respond to the actual words that were coming out of my mouth?! Finally it clicked with me that, for her, the "how" WAS the greater issue. She wasn't ready to hear the what because she couldn't get past the how. In other words, my tone mattered a great deal; more than I had initially realized. Over time, I came to view a careful and deliberate tone as, essentially, a prerequisite to any fruitful conversation.
I think this personal anecdote has application in the atheist movement. Atheists, by their very nature, are content focused. And this is perhaps especially true for those of us who used to be deeply committed to faith. To reject a "personal relationship with Jesus", that you once heartily embraced, is to, in effect, de-emphasize your own emotional triggers (God loves me and has a special plan for my life, I know I'll see my grandmother in heaven someday etc.) in favor of a heavier emphasis on the rational and the empirical (the evidence doesn't support these conclusions, therefore I must reject them, and so on and so forth).
I believe that a lot Christians have the same problem, with many atheists, that my wife used to have with me during certain of our disagreements. They can't hear what atheists are saying, because of how atheists are expressing themselves. Now, some might take issue with my use of the word "can't" here. Surely Christians are mentally capable of separating style from substance, aren't they? Maybe such believers just don't want to consider what atheists are saying, so they use how something is being said as an excuse to dismiss it. I happen to think this is exactly true, but it only further underscores my point. My fellow atheist, do you want Christians to ruminate on the content of what you say, or would you rather they focus on (what they don't like about) your style? You have to make up your mind. If your goal is to reach across the divide, as mine is, than you need to pay close attention to tone.
Dan Savage's recent talk will serve to be a great illustration of my main premise. I recently overheard some Christian friends of mine discussing his comments. At first, I actually got a little excited about it...how will they respond to Savage's contention that the Bible contains "bullshit", I wondered? What specific evidence will they bring up, to counter this claim, and show the reliability of the Bible? Or how about his suggestion that "we can learn to ignore" what the Bible says about homosexuality, just as we have done with the issue of slavery? Notice that each of these thoughts is content focused.
But, as you've probably guessed by now, fully 100% of the interaction, between my Christian friends, focused on Savage's tone. Not once did they so much as even bring up the potential merits, or lack thereof, of literally anything that he had to say. They talked exclusively about how he said it. To put this another way, Savage's tone distracted from his message. This is immensely frustrating to someone in my shoes. When the believer can (justifiably) accuse their opponent of being rude or, in this case, even hypocritical it feels like nothing short of a checkmate to them. It really does. In the believer's mind they have "won" the argument right then and there. As Dr. Phil often says, perception is reality. Their reality, in this case, was a "win" for team Christian (who stood by their convictions by walking out on Savage) and a "loss" for team atheist (who just proved, once again, how hateful and spiteful they are).
Friendly Atheist hit the nail on the head, "...when you're giving a talk about how gay people get treated like shit, don't use words like 'pansy-assed' to describe the reaction of the kids walking out on you - it just makes you look like a bully yourself, even if you're not."
Exactly.
I also agree completely, with people such as Greta Christina, who say that atheists have legitimate reasons to be angry. There's no question about it. But, as Christian speaker and author John C. Maxwell points out, "people don't care how much you know, until they know how much you care". This may sound a little cheesy, and frankly it is, but it's also true.
Dan Savage made some valid points, that Christians ought to really think about, but sadly they're very unlikely to do so simply because he didn't choose his words carefully.
So, to the atheist, I would close by asking you to reflect on your personal goals. Do you want Christians to consider the things that you say? If so, you've got to keep your emotions in check. To not do so is to heavily reinforce the prominent "angry atheist" stereotype, in the mind of the Christian, which is a close cousin to the terribly misguided "deep down they know there's a God, and are just rebelling against him" line of thought. It's akin to shooting yourself in the foot.
To the Christian, I would ask you to look beyond your gut reaction to controversial comments, like those made by Savage, to hear what is really being said. It might be something worth taking seriously. If you focus on the how, to the exclusion of the what, you are simply distracting yourself from deeper thought on the issues at hand. And Savage is right about those.

