I think it's never a good idea to allow a false idea to stand if you are in a position to correct it. Here, I'm talking about factual errors. For example, if someone says, "The Bahá'í Faith is a sect of Islam that exists only in Iran" in my hearing, I'd feel duty bound to say, "No, it's not." And offer proof if necessary.
As it happens, I spend a significant amount of time defending religion in general from occasionally virulent and bizarre attacks on it, both online and in what we like to call the Real World. Yes, there are certainly haters of religion in general or haters of specific religions who are so dogmatic in their thinking that they will spew hateful rhetoric and refuse to engage on a rational level. I've had the experience numerous times in which the person I was having a dialogue with made ridiculous assumptions about my beliefs based on God knows what and refused to listen when I tried to correct them.
An example is when one fellow told me that I believed the world was 6,000 years old and that science was evil just because I said I believed in God (this was on an atheist blog and the fellow had seemed well-educated and intelligent up to this point). When I said that the was wrong on both counts and that my faith taught that science and religion are in harmony, that faith and reason went hand in hand and that evolution was the mechanism by which life has come to this pass on the planet, he simply didn't know what to do with that information. It could not be so, he insisted. So, I quoted from the Bahá'í Writings: "Scientific knowledge is the highest attainment upon the human plane, for science is the discoverer of realities." — Abdu’l-Bahá, Promulgation of Universal Peace, p. 138 (23 May 1912, Cambridge, MA)
At this point, the fellow abandoned rational discourse, began peppering me with cherry-picked verses from the Old Testament and Quran, repeatedly told me I was "escamoting" (which is a fancy way of saying I was dodging his assertions—I wasn't dodging, I was just saying, "No, I really don't believe that") and began psychoanalyzing me and telling me what I really believed, meanwhile intentionally mangling the word Bahá'í (Bahaooey, etc). All my attempts to re-engage in a rational way were ignored or mocked.
My husband asked why I continued talking to this guy when it was clear he wasn't actually hearing what I was saying. My answer: I wasn't really talking to him once I realized he was dogmatically compelled to explain me away. I was talking to the people who were monitoring the dialogue and who occasionally weighed in, or sent me private messages in support of the calm, even loving way I was handling this guy's mockery and condescension, or friended me in social media or began following my faith and reason blog (Commongroundgroup.net) because of it. These people became my friends because of this fellow's animosity.
That guy may not ever come to realize that dogmatism is not limited to religious people or that it isn't necessary to be dogmatic to be religious. He may never realize that there's a difference between what a religion teaches and what it's followers do. He may always believe that all religion is superstitious, Bronze Age nonsense. But those other folks, the ones who were listening and watching came away with a completely different impression of religion and its potential relationship with reason than the one they went in with.
