In everyday life, there are really only three philosophical issues with which people are concerned and should be concerned: God, ethics, and justification.
Other more esoteric concepts are of less importance. For example, the meaning of life. It gets discussed all the time, but what good does it actually do for us when we go to the store for milk?
Ethics is critical because right and wrong are central to our actions involving other people. We do what's right and shun what's wrong. Thus, those two adjectives are REALLY important to define.
Justification is important because we have to understand the reasons behind our actions. My dad will frequently be heard saying that the most important things in life are knowing who you are, what you're doing, and why you're doing it.
Those first two parts sound simple but are really tough. Importantly, I also think that a person who completely lacks those first two parts can bumble happily through life. But why you're doing something is so important. If you don't understand that part, your actions are chaotic. Anything can happen because you don't grasp the motivations of your actions. You are a slave to your own impulses.
Justification allows us to semi-quantify our motivations. God is the complete abdication of justification. There is no philosophically strong way to rely on God as a way to explain our actions. It is lazy justification.
That's where the disconnect between religion and science lies. A religious person can easily be a scientist, but they cannot fully believe in the precepts of analysis and justification since a critical part of their life is predicated on something that is totally devoid of justification.
That is my answer to those who argue that I should simply leave people alone. That religion has a small effect on people's everyday life, and that they would act and be basically the same person with or without religion.
That's entirely possible, but it's also possible that people would be different. No, I think the question of God is critical and that people would in fact be different, and be different for the better. This study drives home the degree to which people rely on God for either direction or justification for actions.
God is important. These people are directing their lives and having an effect on society and those around them based on a philosophically baseless belief! So rarely does philosophy come into the average person's life, but it does here, and does so in a big way.
Is it any wonder that people once used religion to justify the oppression of women, blacks, and other religions? Or that we now have a war being waged against homosexuality? Or that we now have an "our God can beat up your God" situation going on with Islam? Or that evolution is tantamount to heresy? Or that Fox News is WATCHED?
Baseless beliefs are bad, especially when people don't know that they are. It is in this way that religion is fundamentally dangerous.
God Helps with Personal Decisions, Most Americans Say (LiveScience.com)