When I talk about religion some people ask what damage it does?
Of course, the first thing that comes to mind is jihadists suicide bombers (or worse, non-suicide terrorist, at least the suicide ones kill themselves too) or christian fundamentalists denying medical care to their own children because it goes against god's will.
Then they specify that they were talking about the more discreet believers. You know them, the ones who don't read their holy books, wouldn't believe what is written on them but couldn't care less anyway. Those are the ones attending their services without thinking about what they mean and whose behavior is hardly influenced in any way by the religion they say they follow.
Actually, they are not far from behaving as atheists, except for a few things.
First thing is they waste their time attending those services.
Second thing is they keep teaching their children that religion, in the best case making them the same kind of person they are. In the worst case, they're easing those children way into damaging others because of their religious beliefs. Any way you look at it, any believer is more easily converted into a religious extremist than an atheist is.
Third, and this damages their children even if they never go farthest than their parents went, even the discreet kind of believer is used to discards any fact in conflict with their beliefs, and that is a custom easily extended to fields different from the religious one. Usually politics, economy and society opinions are the first ones being fixed thanks to that disregarding of anything conflicting with the opinions they hold, but they often don't stop at that.
That third damage is the more dangerous, because it's more subtle but more easily taught, and a necessary condition to advance from normal believer into hardcore believer. That third problem can be summarized as having the ability to turn their critic thought off, except it's not under their control.
The critic thought is what makes us react when something is incoherent or inconsistent, what makes us realize when somebody is trying to manipulate us, because they are usually incoherent with other things they say or do, or because they're incoherent with what reality is.
So, that lack of critic thought is what lets other people take advantage of us, and teaching our children that normal, standard religious way, no matter what particular religion, is making more difficult to them to develop that critical thought, so necessary in our lives
That's one subtle way the "normal" believers of every religion burden and damage everyone (else and themselves).