It's not that they're wrong, so much as they become complete a**holes while being wrong, telling people that they are going to suffer. We see it on this very forum.
And while you say you have no interest in holding anyone in contempt, what you're doing in the meantime, is saying both sides are somehow equal, and in some ways, holding both sides in contempt. Yet at the same time, agreeing with me that both sides are not the same.
I think that Christian fundamentalism, and with it Biblical literalism and absolutism, are minority positions, not only within modern society but also within the United Church and other liberal Protestant denominations. The radical Christian Right defeat themselves with their own rhetoric. Battling them only makes them more defensive of their indefensible position. If given enough rope, they will eventually hang themselves. Conducting rational arguments by quoting reams of scripture works only for those who believe in scripture as absolute truth, and those who do are becoming increasingly irrelevant.
But what about radical atheists or anti-theists? If they believe in logic as the only method of finding truth, then they might also be mistaken. According to many philosophers, scientists among them, there are two diametrically opposed kinds of truth, the small t truth of the analysis, and the capital T Truth of the synthesis.
It appears that reality ultimately is nondualistic: an inseparable, unified whole: a singularity in a state of synthesis. Analysis is only one possible way of apprehending the singularity. But analysis necessarily fragments the singularity, and therefore gives us a fragmented and distorted picture of reality. Reality, as it really is, can only be experienced in the pure, unconceptualized experience of reality. Experiencing reality in its pure "isness" is experiencing ultimate Truth!
Those of us who dare to experience ultimate Truth, and immerse themselves in the pure, unconceptualized experience of reality, experience the unity that underlies all diversity. They are overcome with awe, and experience unitive love. They experience what Christian fundamentalists extoll as "Christian virtues." Some atheistic mystics even go as far as metaphorically describing their experience as an "experience of God." Allan Watts called the stance of atheistic mysticism "atheism in the name of God."
I would like to emphasize that by "mystical experience" I mean nothing more and nothing less than immersing oneself in the pure, unconceptualized experience of reality. Anyone can do it. One only needs to silence the incessant chatter of one's thoughts, and go deeply within, in silence and stillness.