You have been indoctrinated into believing that if you don't believe into some God you are automatically destined to be an immoral person. I don't know where you got your idea. Church?
People are inherently good or bad, regardless of their religion or irreligion.
I am telling you the Bronze Age morals and world view is not the way to go forward. If it was not for the secular movement, Christians would be burning scientists, gays and atheists at the stake.
I can assure you I have not been indoctrinated. I started from a position of agnosticism and build up my worldview step by step starting from a deep examination of my basic assertions. My conclusions do not come from dogma but logical deduction. I have also outlined my beliefs and the logic I used to reach them in some detail. See: Empiric Argument for God.
I am not a member of any religious denomination. For the past 20 years I was a strong agnostic abandoning that position only after great consideration once I realized it was untenable.
I understand your fear of fundamentalism. It is valid and has merit. What you seem to be missing is the fact that fundamentalist extremism has nothing to do with God. Extreme fundamentalism follows from the false human assertion that my ideology represents a perfect understanding of truth and all differing ideologies are therefore worthy only of suppression and extermination.
The Nazi's were darwinian fundamentalist the Communist utopian fundamentalist. The world today is full of fundamentalist of all stripes some associated with traditional organized religions others associated with secular causes. Yes fundamentalism can be very dangerous but if you think it is an organized religion problem you are mistaken. Extreme fundamentalism is a widespread human problem and taking God out of the equation simply makes the problem worse.
You argue that rejection of God is the path forward. My response is that you are utterly failing to appreciate the dire hazards of that road. Don't take my word for it. Learn from Fredrick Nietzsche a fellow atheist and one of the most devastating critics of institution Christianity that ever lived.
See:
Nietzsche and Christianity
and
Nietzsche and Nihilism