Why people are religious

[Whateverist]

If I find out someone is a theist, then I assume their method of arriving at that conclusion is probably faulty. 

I don't really think of what led them to be religious as faulty empiricism or cosmology.  Ones religious beliefs are not what one ends up with at the end of a long and fruitful search for what can be found in the world.  Religious beliefs arise as a result of what one believes is true about their experience phenomenologically.  Faulty empirical conclusions are just an unfortunate by product, though it is mostly the literally inclined fundies whose objectivity suffers the most.  Those theists who accept religious beliefs allegorically are more likely to remain capable of maintaining an agnostic stance toward dogma.