Atheism doesn't make any claims, it's a description of a state of mind, the state of not having a belief in any proposed divine beings. Theism is the opposite state, the state of believing that at least one divine being is real. The only claim an atheist is making as an atheist is that atheism describes their state of mind concerning the existence of divine beings. The only claim a theist is making as a theist is that theism describes their state of mind concerning the existence of divine beings. They are both singular opinions, and it's reasonable to accept someone's self-report on their internal brain states unless their actions show that they're lying.
Most atheists I'm familiar with don't say 'there's no evidence for God, therefore God doesn't exist'. They are far more likely to say 'I'm aware of no convincing evidence for God, therefore I don't believe God is real'. And that is a perfectly reasonable position to hold about any nontrivial proposition for which you're aware of no convincing evidence.
Most atheists I'm familiar with don't say 'there's no evidence for God, therefore God doesn't exist'. They are far more likely to say 'I'm aware of no convincing evidence for God, therefore I don't believe God is real'. And that is a perfectly reasonable position to hold about any nontrivial proposition for which you're aware of no convincing evidence.
I'm not anti-Christian. I'm anti-stupid.