I live for enemy audiences. I would prefer to speak to a well-sorted advocate for religious thought that with someone who already generally agrees with me.
First off, the enemy encounter is less-frightening. With someone who already agrees with me, they might see me as intellectual competition, or I may fail to impress them. Someone who has thought about all the same stuff as me might determine me to be a total idiot. I'd rather have someone who's gone on an entirely different track.
I also want the competing viewpoint because it's the best way to engage in the classic dialectic. An argumentative exchange of points and counterpoints, where at the end, both parties leave with a greater grasp of the subject. No synthesis needs to be achieved. Both parties either leave shaken or ever more resolute in their original belief, but both outcomes are an advancement from where they started.
It's from that standpoint that arguments should not be about winning, but about achieving something separate from the encounter. In this way, arguments are never seen as something worthy of raised voices. Obviously, if we're talking about arguments that could lead to action, such as going to war, raised voices might be necessary, but in this ideal, academic setting, raised voices just make you look like an ass.
I've always felt that this goes back to Socrates. Where Soh-crates generally seemed more interested in showing the errors in others' thoughts, in his encounter with Protagoras, he discusses not a desire to prove Protagoras wrong, but to bumble towards truth. And whoever is proven correct is of no importance, just so long as someone is proven correct.
It's for this reason that I love science. It has been a massive, ongoing dialectic, with new sides and new evidence arising daily. The dialectic is our only path to something resembling "truth," whatever that may be, and science is the biggest one in history. That makes our country's ever-surprising fear and distaste for it all the more depressing. I can only hope all those that speak against science, be it climate loonies or people who support Intelligent Design, will all soon be dead from either old age or acute stupidity.