In my own experience, they do it to make their religions seem tolerable to the rest of us. After all, tolerance is only a rational philosophy if the object of our tolerance is not going to turn around and treat us intolerantly the first time he gains power.
A friend of mine insists that the vast majority of religious folks are sincerely nice, reasonable people who are not swayed by the extremists. When I pointed out that those nice, reasonable people persecuted Jews for a thousand years and then stood by while they were herded into camps, all he could do was whimper, "Yeah, but they didn't know they were really going to be murdered there." As an average American with a few Jewish branches on his family tree that were pruned by the Nazis, even I believe that statement, but it doesn't excuse them for the events leading up to it. This guy didn't even know that the reason Egyptian civilization can only be found in museums is that another branch of Abrahmists destroyed it in the name of Allah.
The history of Abrahamic religion is the history of its extremists, and the only reason those extremists acquire enough power to make history is that the "nice, reasonable" faithful people fall under their spell. The faithful are easily swayed by the extremists precisely because religion is irrational. There are no objective criteria by which to judge an extremist who exorts you to burn the Aztec libraries, hang witches, throw rocks at ambulances driving through Tel Aviv on the sabbath, or knock down the Great Satan's commercial towers.
But they don't want to admit that to themselves, and they certainly don't want to admit it to us.
Agreed.
I would presume atheists are as likely as theists to conform; as is evidenced by how they justify the idiots on "their side".
e.g. this
He's speaking truth to power. Why so reactionary? Can you prove he's an idiot somehow? What is it you don't agree with?