When it comes to faith, there are three main branches. Theist, atheist, and agnostic. Theists have a belief in a higher power, and atheists have no belief in a higher power. Agnostics are the people who are comfortable saying "I don't know".
People can be agnostic and still lean more towards an atheist or theist belief. It's when a faith system is poised to be a matter of fact that it becomes harmful to healthy communication. Once a bias becomes bigoted anyways.
Sorry for stating the obvious, but some people are so cocky when presenting their faith, whether it's atheist or theist, that it appears they need to be reminded of their illogical "matter of fact" conclusions.
Let me give you my opinion on this, because it is not that far removed from yours.
I've said for a while now, and received plenty of both positive and negative feedback for doing so, that Theism and Atheism are flip sides of the same coin. Both involve a belief that something is or is not, without the ability to prove it. Breaking it down along definition lines makes Theism nothing more than the belief in God or Gods. Atheism is then the disbelief in God or Gods. The issue then comes down to a suggestion both make but neither really knows.
I refer to them as flip sides of the same coin for several reasons. One, they do tend to make that profession of faith as a "matter of fact." Two, they both end up being a system of belief as neither is provable in terms of scientific process or empirical reason. Lastly, they both tend to claim they are right.
Agnosticism then is about coming to the conclusion that these systems of belief are based on the unknowable. Someone who neither does believe or does not believe in a God or Gods is suggesting what you conclude. We do not know, and perhaps cannot know, in present context. It takes a system of belief to bridge the gap.
It is easy for any of this to end up in conversations based on anger or arrogance as no one at the end of the day wants to be told that their system of belief is wrong, and that is one key reason why there are so many systems of belief out there. Humanity for as long as recorded history tells us has continually come up with new systems of belief along the way to explain what otherwise could not. At least until the age of philosophy and science told us to question then discover.
It has been my experience that more times than not people to lean agnostic tend to get there by a level of resolve that neither theism or atheism allows, and as such tend to be the least militant about their position on the matter. Because, and rather ironically, there is less ego involved in having to be right about "not knowing." You end up with a modest, perhaps humble, interpretation on the limitations of humanity in the obtainment of that knowledge that neither theism or atheism is really interested in. We already know why, systems of belief are not rooted in facts. They are rooted in their belief one way or the other.
