I don't feel like the type of person that you are is affected by whether or not you believe that God exists. For the record I did not attend church for my entire childhood until I was about 10 years old because my parents did not take me to church or talk a lot about God, but I still feel as if I was as good a person as someone could expect to be in my position, and I still feel as if I am fine in terms of who I am now in spite of the fact that I only sporadically attend church. Moreover, comparing God to someone like Hitler or Stalin is like comparing apples to oranges, because no one is necessarily a bad person in the grand scheme of things regardless if they believe that Hitler/Stalin were good people, or if they do or do not believe that God exists. This might be different if someone was consciously aware that Hitler or Stalin was bad and then they still chose to regard them as good people, but for instance if you are conditioned to believe that killing people or treating people bad is a good thing, then chances are that you may believe that someone who does these things is a good person, even though this does not make you yourself a bad person any more than it does someone who thinks killing or mistreating people is bad. Likewise, someone who does not talk a great deal about God or does not believe that God exists is not necessarily any worse of a person than someone who does believe that God exists and always goes to church, assuming that they are both morally good people who do nothing wrong and have no desire to do anything wrong in their own mind. It really just depends on their actions or what they have been conditioned to believe.