The point was that atheists have no disagreement on what it is...

The point was that atheists have no disagreement on what it is that defines atheism, which is a lack of conviction in the existence of a God or gods.

So it's completely irrelevant to say that atheists disagree amongst themselves on matters that have nothing to do with what defines atheism, a lack of conviction in the existence of gods......which is what you did when you said that atheists also don't agree amongst themselves.