Occasionally the question arises in the skeptical community about what is and what is not a skeptical subject.
There are various opinions about what is fair game and what is not. Dividing lines that often come up include: matters of opinion; politics; and subjects where evidence is irrelevant (though there is the strong implication that the first two are the latter-most.)
There are those who simply won't touch religious topics. And not just those who happen to be theists and skeptics. I understand why that sub-set of skeptics might avoid the subject, it's the others that make me curious. I, for one, wax and wane over my interest in atheistic matters. There are a few aspects of the great debate between atheism and religion that tend to fire me up (morality and evolution education being at the top of the list) but that's another post for some other day. Point being that I don't shy from talk about religious matters when I have something to say. Sure, if I'm feeling bored of the debate I won't bother, but that is patently distinct from considering the subject verboten. Similarly, there are those amongst us who have tired of the entire discussion, but aren't philosophically opposed to commenting on it.
Atheism strikes me as possibly the biggest single vein of skeptical thought (quackery being a contender, as well) and one of the most ubiquitous aspects of our lives regardless of your position on it. Why then would admitted atheists deflect any discussion on the matter? I really have no idea on this one. If anyone has any thoughts, please enlighten me in the comments. As it stands all I can imagine is that they themselves have too many close connections to people who are themselves religious that they do not want to strain. I can hardly argue the value of that choice - indeed it is just that, a choice. I do tread lightly where my devout friends and family (not many of the fomer, even less of the latter) are concerned. There is sort of a respectful detente at work. I know they believe in the Uber-Darwin and they know I have an abiding understanding of the earthly one and all his buddies in the mythos of science. We simply don't make it a topic of conversation. I don't worry about the possibility that they might read this blog post (Hi, folks!) and take offence, and I don't get my nose out of joint over Facebook statii that thank Jesus for random and zero-sum events.
But then there are things like politics, economics, philosophy and even art. (All over-lap conveniently ignored for simplicity.) Why should critical thinking not be applied to such things?
There absolutely is a difference between the complex, occasionally unfalsifiable, and often opinion-based territory of such subjects and the quantifiable, evidence-based grounds of science - but that doesn't mean that logic and reason cannot be applied. Politics cannot alter facts, but facts can and should guide political process - I don't think there is much to argue about there. Further, a bad argument, regardless of whether it is applied to a matter of opinion or fact, is still a bad argument. Basing a position on a logical fallacy does not make the position wrong, but it does invalidate the choice to base the opinon in question on the fallacious argument being applied. Matters of aesthetic or social preference may not be reachable by logic alone, but the defence of those preferences can be girded by a liberal application of logic.
I'm not saying we all need to live our live devoid of emotional choices and responses. No, not me - ever. But that doesn't mean that our opinions and even our feelings can't, once we've experienced the visceral knee-jerk reactions that are our Human (Not Vulcan.) nature, be re-considered. Science and fact can't be determined by emotion, but that doesn't mean that we can't reconsider our reactions - particularly those that result in long ranging effects - and possibly see through the inherent errors of our position. Perhaps the choices we make are "correct" (whatever that means n the circumstances) in the first place, but by determining the weak points in the foundation of our opinions and reconsidering on the basis that our position should not be formed around a false argument, we can only serve to improve our position.
So, what is out of bounds? I would suggest that nothing should be. Absolute truths will be harder (or impossible) to reach on many paths of inquiry, but determining what is patently false will always be a valuable guide for pencilling in your provisional viewpoint.