Atheism is mainly a disbelief in the God of the Bible. Atheists choose not to believe in either God or a devil and so not in heaven or hell either.
Although atheists claim disbelief in any god, everyone worships something- whether themselves, another person, power, money, science, or traditions. So if atheists claim to believe in science rather than religion then their “god” is actually science. Everyone holds a worldview.
Atheists seem to be mad at God and other religions since they fight so vehemently against any religious expression in public. Atheists seem to fear free expression of religious viewpoints.
Actually the great minds and humanitarians in the past have had their roots in Christianity not atheism. It was Christians who founded and still operate orphanages, hospitals, and other charitable works. Many of the great scientists, past and present, were and are not atheists but Christians. Not done with the idea of earthly reward, Christians do their good works because they love and serve a Holy God. If atheists are involved in good works it is for their own feeling of goodness.
And how do atheists decide what is good or moral? Take a poll? Vote with 51% winning? According to the atheist the existence of evil and good in the world are in the eyes of the beholder. Since the basis for atheist morality is relative, based on what each individual believes is moral and good at the time; that basis is liable to change at any moment. Atheists have no god or guiding principles to serve as a foundation for their beliefs.
Wars and evil come about in this world not because we are not all atheists; but because we are all sinners who need to worship the true Savior Jesus Christ who freely gave his all for us.