As someone who identifies as an atheist, and who is happy to criticize religion (often called a "new atheist"), I know I'm in a vocal minority. This is pretty obvious when I interact with the asexual community, where non-religious people constitute the majority, but vocal atheists are still yet a small group. But it's been obvious for a longer time than that. I went to college, I studied physics. There are a lot of non-religious people around. Atheists are a much smaller group, and new atheists are smaller still. Despite being at a university with tens of thousands of students, we only managed a small and disorganized atheist group, and even there, not everyone thought of themselves as an atheist. All the numbers I've ever seen also confirm the trend, though I'd rather not dig into the data right now, so let's leave that as hearsay.
I don't think there's really that much to say on this subject, but I'd like to briefly explain my relationship to the "quiet majority".
I do not see the quiet majority of nonreligious people as allies, really. I do not see myself as representing their point of view, or them as representing my point of view. In fact, that's not even the relationship I have with other new atheists. I mean, new atheists are not a very cohesive group, and there are some factions and prominent speakers that I actively dislike.
Non-religious people, as a general category, are even less cohesive than new atheists. It's hard to even enumerate the different "kinds" of non-religious people. There are people who still essentially have Christian (or other) views, but disassociate with religion for some reason. There are people who are part of some "philosophy" like Taoism, but for some reason don't consider it a religion. There are people who take stuff from multiple religions. There are people who are culturally, say, Jewish, but don't believe in any of it. There are agnostics who reject the term of atheism for philosophy reasons. There are people who have other idiosyncratic views on the terminology, preferring things like "humanist" or "ignostic". There are deists and pantheists. There are "not that kind of atheist" atheists. There are people who just don't think about it much, and thus it would be impossible to define their position on the subject. There are atheists who think religion is bad, but just don't care to make any sort of deal out of it, or who even resent that I make any sort of deal out of it. And probably a bunch of other stuff I haven't thought of, especially when we venture outside of US culture. That's the other thing, I know new atheism is primarily a US/UK thing, though not exclusively so.
Yeah, it's really hard to generalize across such a disparate group. Maybe some of those people completely agree with me on my criticism on religion, maybe we share other common ground. But that's something we need to figure out on an individual basis (both by individual people, and by individual topic). We can't rely on labels to do the work.
I do have some specific beefs with other non-religious people (not all non-religious people of course, but enough that I have that negative association). I see other non-religious people as being the source of a lot of tone policing of new atheists. It's all "atheists are being too angry, don't they realize that religion fulfills certain needs?" I still hear this sometimes, I think from people who don't realize that we've already heard it all when the topic was beaten to death in 2007-2011.
I have a beef with people who say they're "not that kind of atheist", because, well, that's obviously based on some kind of opposition to what I stand for, or for what they think I stand for. You don't like me, I don't have to like you. Along similar lines, I often, but not always, have beefs with people who identify as agnostic. Not because I think there's something particularly wrong with agnosticism, but because some people choose that label because they don't like something about new atheists. (I suppose I have the more general beef that self-identified agnostics are choosing to emphasize philosophical hair-splitting over more important topics, like religion's influence on society, but that's not as big of an issue.)
Lastly, I don't agree with all the supernaturalist non-religious people. I oppose supernaturalism.
So this is all just to say, if I have any readers part of the quiet majority of non-religious people, I know you exist! I've talked to people like you before. You might be okay by me, or you might not be. I don't really know! Hello.