I think that one should be respectful OF the religion of others. That doesn't mean we actually respect their religion. It simply means that there is little or nothing to be gained by anyone by being disrespectful of someone's deeply held beliefs. So, unless there is some direct threat posed by the religion (or other belief, for that matter) then, unless you are invited to debate the matter, you should mind your own business. [emphasis added]
This raises the very important question: what does it mean, to be "invited to debate the matter"? Is this limited solely to cases where a person comes up to you and specifically requests, in so many words, a debate about religion? That's not reasonable. I would argue that any time a person puts their beliefs into the public arena -- by arguing for them, by offering them as a reason for some action, or simply by declaring them to be a good idea -- then they are implicitly inviting debate, discussion, and critique.
No one gets to publicize their ideas, beliefs, or opinions and then also say "because these are deeply held beliefs, you can't disrespect them, question them, criticize them, etc." On the other hand, if a person generally keeps their opinions to themselves, then it would be quite rude of me to make the effort to discover them and then go out of my way to criticize them. Unless there is a real concern about someone being harmed, I agree that such people should be left alone.
There is also the obvious question of what constitutes "disrespect." Do the believers get sole jurisdiction over this? That also wouldn't be reasonable -- let's keep in mind that however deeply held a set of beliefs are, in the end they are still a set of opinions and should be handled similar to how other opinions are. Democrats don't get to shut down conservatives' critiques of their political beliefs because such critiques are "disrespectful," do they? Some progressive and liberal political beliefs are very "deeply held" too, after all.
What does it mean to be "respectful of," though? I've yet to see a definition of "respect" which is both justified and which atheists are not generally doing. In nearly every case, the "respect" being demanded is really a form of high esteem or deference, and it is unreasonable for adherents to demand that of their religion from outsiders.
To me, it is about freedom. I've spent enough time in my life (as a cult member) of knowing for sure that everyone outside my religion was wrong and going to hell for being wrong. It was up to me and the allegiant few to save them, to dismantle their false beliefs and bring them into the light of the One Truth.
Sorry, I've been there and done that. Those atheists who would seek to purge the world of all religion are misguided. Extremism, fundamentalism, and "Chosen Few" (nice way of saying "cultic") ideologies.... well, we should try to rehabilitate those people. But to purge all religion? Sorry, it cannot be done. And, even if it could be done, I don't think it should be done. History has shown that when one religion fails a people, they don't often resort to freedom from religion. No, they either adopt another religion or invent a new one. Better the devil that you know, than the devil you don't: new religions have a tendency toward being cultic.
For the rest... non-extremists, despite a variety of beliefs, tend to live decent lives and their fanciful beliefs give them some comfort. How dare I be so arrogant as to say that I should be obliged to "free" them of their beliefs -- especially when those beliefs don't really matter all that much anyway. Yes, it is obviously true that a great many religious beliefs cause oppression and repression. We should encourage moderation in such cases.... help them see the value of toleration for those with whom one might disagree.
It's true that all religion won't be purged. Is this a reason not to argue against religion and superstition? All murder won't be eliminated, but we still have laws against it and still work to stop it. Total success isn't a standard which should have to be met in order for a goal to be pursued, is it? Add your thoughts to the comments here or join the ongoing discussion in the forum.