That's an unfortunate misunderstanding about atheists, unfortunately embraced by most atheists. It's like when they discovered they don't believe in a god anymore, any trace of evolution in their view of the universe just freezed. This is bullshit. I can easily call myself secular humanist, vaguely militant-atheist, zen-atheist (there's also zen-christians and zen-buddhists, don't worry), and I doubt very much I will die with the same labels.

People change, and people are different. Grouping the understanding of life of Einstein or Gates in the same category as every 15-year old who just rejected religion is a limitation I strongly hope we'll overcome in the coming years.