Since technically, I am an atheist, I'll reply:
What do atheist lack in terms of the brain's firmware?
Maybe.
A Calvinist-like outlook, and some views within Hinduism, for example, do hold that people are effectively predestined (forever; or at least for this lifetime) and so there is only so much they can do, in terms of religiosity. And whatever they can do may not be enough to manifest as any kind of recognizable or actionable religiosity.
But if we propose that nobody is born a theist, but that theism is something one learns from other people, then the absence of suitable theistic role-models, teachers and opportunities in a particular person's life so far could completely or in part explain why some people are theists and some aren't.
If you read the posts the religious try to be reasonable offering a bridge,
They do that only sometimes. Other times, they impale people or burn them at the stakes.
while the atheist burn bridges out of an irrational impulse.
Sometimes, it is actually the atheists who are in the position of having to emotionally parent the theist. Sometimes, it is the theists who throw a tantrum, and the atheist then has to be the calm and reasonable one - if there is to be any meaningful communication, that is.
Is the goal to remain limited to the animals and avoid having to deal with the extra or is there lack?
Needless to say, I'm sure your post will upset many posters here. Fortunately, I am old and experienced enough not to get too worked up about such posts as yours.
As noted earlier, your outlook doesn't take into account the possibility that for a person to become a theist, suitable theistic role-models, teachers and opportunities may be necessary, and that without them, a person's religious potential cannot unfold.
I think you are both idealizing theists and theism ("Any theist is a good enough preacher for anyone. If any theist preaches to an atheist, and the atheist doesn't convert, this is solely the atheist's fault"), as well as trivializing theists and theism (as if theism and interactions with theists would be essentially no more than a matter of uttering the right mind-blowing mantras that instantly transform a person upon hearing them).