As the offspring of a fervent atheist I can assure you it can take on the the same fixed rigidity, intolerance and control as any devout religious observer, with weird rules and rituals and beliefs just as seemingly random and inexplicable.
I was initially brought up as officially a "Practicing Atheist," double underlined on every document. The extremeness meant it was picked up on and I faced questions everywhere from a very young age.
Actively rejecting religion was an important expected part of life and identity.
Formally excluded from school assembly, RE classes, carol singing/listening, hearing the Sally army band from many streets away, or anything connected to Christmas or Easter. School, society and parent extended this to cover snow covered post boxes, robins, snowflakes, glitter, tinsel, Xmas trees, fluffy chicks, bunnies, chocolate eggs, and a huge host of other things.
Clothing choices dictated by not appearing certain ways. Kneeling forboden. Colored light pooling on the floor through glass must not be played in...
Taught to perceive all external authority as the stupid untrustworthy sheeples from the off. My parent was the only authority in life.
The tip of the iceberg a child can be subjected to under the name of atheist..
The importance of controlling what I did or didn't believe meant the wrong look at the wrong moment or glancing at the wrong thing, could end very badly.
Then adults in school would say they could tell what I was thinking, so I developed practicing 'shielding' my mind and thoughts, appreciation of beauty of many things, and becoming mentally blank and neutral around everyone to mentally survive my fear of both 'sides.' I was just a powerless kid.
My parent was so terrified that their control of me would end if I was 'brainwashed' by religion, that they worked to 'brainwash' me in their non belief.
Ironically I ended up in the 'care' of nuns who wanted to battle 'Satan' for my soul if I had one.
No matter what I thought, believed or didn't, someone had got to me, I could not have or own my own unfucked with thoughts on anything, ever.
Control is control whatever philosophies or words are used to excuse or rationalize it.
NAAALT obviously, but atheism can be no different to any other dogmatic system of beliefs when practiced by controlling individuals.