On the subatomic level it leans towards that. But at the level of humans and acts the probabilities are so astronomically small, the probabalistic nature of reality is considered moot in relation to our acts, beliefs, opinions.
For the most part, that's true enough, but actually there are some areas where pure quantum indeterminism can have huge and dramatic impacts on the course of our large scale reality.
We can contrive scenarios extremely easily, for instance I could become a quantum serial killer and decide who to kill based on the outcome of quantum events. These days the random numbers used in gaming machines are sometimes generated by quantum devices, so you could become rich or not purely on quantum chance.
On a more natural note, there are quantum processes which can give you cancer, for instance getting zapped by a cosmic ray or even just the usual UV light. Then of course there is the whole big bang singularity where all this seems to have come from.
The human brain isn't well understood either, quantum mechanics may certainly play some role in how we think. I don't think there is much evidence for it at the moment, but we don't know much either.
Ok so that wasn't much of an argument for it's impact on beliefs, opinions etc, but it should certainly be enough to convince you that we don't live in a deterministic universe that somehow emerges from a non-deterministic microscopic world. It is still plenty non-deterministic at our level, or at least it is if the microscopic world is truly non-deterministic.
Certainly it is possible for an atheist to be consistent on all of these things. To be as rigidly lean - occam razor-wise - in all categories as they chide the theist for not being in relation to theism. But I have never met such a creature.
Are you one?
I certainly try to be. Of course one can't always succeed, especially when one isn't aware of the inconsistencies, but the point is that one should always be open and willing to adjust their beliefs and world view to accommodate new evidence and knowledge as it is acquired. It seems to me that religions somehow teach people to not even try to do this, whether that is the intention or not.
Science of course doesn't have all the answers, in fact it has very few answers, but I personally prefer not to try and fill the gaps with some largely arbitrary and culturally determined beliefs. I think most atheists don't really care if theists choose to do this. They DO start to care when religious beliefs take precedent over scientific observations.
Although now we're a little off topic I guess.