Atheism is simply the absence of belief in god or any deity. Its not meant to be a doctrine a moral code or a weapon. Harm does not come from atheism itself, just as harm does not inherently come from religion.
Harm arises when gods or deities are placed above human dignity and disbelief becomes a license for mockery, exclusion, death or erasure of lived experienced.
In most cases atheism is framed as a personal conclusion, but not as a moral superiority. When that happens, dialogue tuns in to a domination and understanding turns into a contempt.
True interlectual freedom whether religious, atheist or agnostic requires humility. It means recognising that reason without empathy can be cold and conviction without kindness can become cruel.
Atheism is a stand for critical thinking and honesty, it must also stand for responsibility. No worldview or gods or deities are immune to causing harm when it forgets the human beings it affects.
The question is not what we believe or disbelieve, but how we treat lives in the process.
When life is harmed in the name of atheism to the point that someone faces death because of being an atheist, then it is no longer about atheism , it is abuse, oppression, intolerance and abuse of human life.