Atheists think about God more than most “Christians.” More so than they would ever care to admit.
The largest organized atheist “religion” would be Buddhism. Their quest for enlightenment is not a relationship, it is a concept.
I wonder if the modern atheist would term Buddhism as a religion... and that would be mistakenly so, but knee-jerk reactionism has a profound and broad horizon.
I think the modern ‘activist’ atheist is in the business of stifling Judaism and Christianity. They never seem to bring the same critique (venom) to other religions.