There are two issues which seem to want to be addressed. The first is swamping new users with responses. I think that this has to be looked at as part of a spectrum of other possibilities. Alternatively, you could have insufficient activity to garner responses, which I think would definitely be a bad sign. You could have a level of posting activity such that any individual thread might be overlooked, which I think would be a sign of poor organization of zones and boards. Frankly, I think that if we assume that fine control over this sort of issue is difficult and places achieving perfection out of reach, then we have to start looking at the direction we prefer to err in. For my money, I think that swamping new users is not the worse option and may well be the best.
The second concern is tone. Obviously, I have a horse in this race. I also don't think my opinion will surprise many here, but the truth is that we cannot cater to the comfort of the users in this circumstance. We will NEVER prevail under those conditions. The comfort offered by religion is simply beyond the scope of what we can hope to offer, and so, those that value that sort of comfort above all else are lost to us already. Restricting the freedom of expression out of concern for the delicate sensibilities of some nebulous group of transitory members, especially on a forum that is expressedly atheist, seems to me an anathema. The other thing that I think bears consideration is the basic fact that this forum is unique, even among atheistic forums, in the degree of freedom allowed its members. That is really, really valuable and important. Why should we endeavor to emulate other forums that already exist in other places? Why can't we be different here? If a Christian desires to debate atheists in a place where respectful dialogue is enforced by decree, there are MANY other places that user can go. This forum ought to be an attempt at something different. I would compare it to my opinion on gun laws. I don't own a gun. I don't use guns. I acknowledge that guns kill far more people than they protect. However, the US has enshrined the right to bear arms in its Constitution, as a founding principle, and I think that is really important. There is a price to pay, but there is a price to pay for ANY choice. In the same vein as I discussed playing to our natural strengths as atheists in honesty and forthright adult conversations, we can play to our strength as a forum and pay the price of loss of those members that cannot handle the straight talk. There are already other religious discussion forums with rules against disrespectful discussion. If that's what you want, go there. Don't change this place away from what it is. Don't kill off the one place where freedom of expression is placed above respectful dialogue. Many of us that are here LIKE this place because of the freedom to express ourselves without barring holds. There IS no other place for us to go. Don't take this away.