To be fair, neither atheists or believers can prove that there is no God or that there is a God, so nobody can prove what reality is.... so it is just a matter of personal opinion or belief.
I would not say that the "reason" atheists do not believe in God is because they do not like the idea that God is greater than they are, because they cannot like the idea that something they do not believe exists is greater than they are. so I would say that is just a personal opinion some people have. Most believers do not have a clue how atheists think or why they think that way, and some believers label atheists out of hand, but since I have been posting almost exclusively to atheists for over six years, I think I know more than most believers. The primary reason atheists do not believe in God is because there is no evidence that God exists, period. I might disagree with that but I still respect it since we all do not look at evidence the same way.
There are some atheists who do not want to believe in God because
God would be greater than they are if God existed, but I do not put you in that category, because I know you. People should get to know people before they form such opinions, Imo. There was an atheist on another forum who said that even if God did exist she would not want to believe in God, and the reason is because she did not like the idea of having to do what God would expect of her because it would interfere with the way she lived her life. I knew that woman well. She hated me because of my firm belief in God and Baha'u'llah, and she tormented me on that forum until the atheist forum owner banned her from that forum because she was telling him that he did not know how to run his own forum, mainly because she thought he should have kicked me off.