There's lots of mindless following (submission, remember?). Just think of the murderous mobs set on by clerics: the lot of them boasting how righteous they are.
If I grant this, it still doesn't change the fact that the exact same things happen with individuals who are not behaving in the context of a group. It isn't a convincing argument for a distinction between group-driven behaviors and individually-driven behaviors.
In the context of what we're discussing, I don't consider mindlessness and submission to be the same thing, and I don't think "mindless" is the correct term to use what is going on. Assuming you believe in free will, mindlessness implies a total lack of conscious choice. In the human organism, mindless behaviors are automated processes, such as the regulation of heart rate or reflexive muscular responses to pain. Submitting to a set of social norms always involves decision-making and "higher order" thought processes; it isn't mindless.
I suspect you call following social norms that happen to be labeled religious "mindless" because you wish to paint them with a negative brush by using this word and do not mean it literally. Would this be a fair observation?