I think there are a lot of atheists--or folks who call themselves atheist, who never really kicked the habit of faith.
They just dropped one crusade to take up another. They are the ones with the evangelical zeal--the ones the Religious folks are referring to when they claim "Athesim is a religion".
I didn't actually go that route. My route was not a rejection of god(s), but a confrontation with faith itself.
I was raised --as are most Christians--to worship faith almost as much as god, Jesus or Bible stories.
"Faith will set you free"
"You got to have Faith" "Ya gotta believe".
It is a VERY pervasive phenomenon in our society where faith is in and of itself a virtue.
Just go to almost any knick-nack home decor place and you will see "Faith" and "Believe" etched in garden stones or embroidered on pillows or as framed paintings.
We can observe the very large numbers of people --especially in the USA--who have left the traditional religions, but could not let go of belief, or religion.
They will say things like "I don't believe in organized religion but…" as if it makes them thoughful. Or they adopt the new-age Wiccan crap, Scientology or other super-woo.
"Fighting for one's beliefs" is considered honorable no matter what the belief is. If I have heard it once I have heard it a thousand times in regard to the CSA.
And running counter to this is the observation that merely having faith in something or believing something does nothing. I have no windows in my office. My only way of knowing if it is raining outside is to go out and observe --believing one way or another will not change the weather.
And of course, in Christianity--especially in protestantism--there is no sin worse than lack of faith.
I can commit unspeakable crimes and find forgiveness through faith--and receive the Lord's favor in the afterlife.
I can be a kind, generous, thoughtful person --yet be condemned to an eternity of suffering because I lack faith.
Lack of faith is unforgiveable.