Take one human, then apply a simple attribute are they religious or not? True some people are not prepared to be classified one way or the other but many will accept one or the other. Now you know one thing about this person no more.
We have been under the despotic regime of religion for so long that there are many flavors of religion people identify with and in part by it’s nature there are few different Atheist schools at least with names and logos. Perhaps the Atheist resists such classifications as they are historically the source of war and more.
Even Atheists have not truly come to understand the freedom from religion they now assert. We are only now starting to develop a new world view in part because we value it but more so because we reject what proceeded it.