Longer history of atheism?
I suppose the history of atheism, measured by many reasonable criteria, is actually longer in North America than in Eastern Europe. Yes, the atheism was state sponsored for 40-50 years in Eastern European countries (70 years in the Soviet union), but it was often imposed on thoroughly religious societies. Practically all intellectual innovations were coming from the West.
Some possible (not experimentally tested and probably false) causes of the differences in atheists' thinking:
1) The communist ideology has used "atheism" and "materialism" practically interchangeably. The latter term has connotations which put it into opposition to all "purpose of life" questions, which are usually associated with idealism (in Marxist terminology, idealism and materialism are two disjoint complementary types of worldview). Therefore, people who consider questions of "purpose of life" important aren't comfortable with calling themselves atheists in former communist countries.
2) The word "atheist" is sometimes used as an insult in the US (rarely so in Czech republic, I have no idea about rest of Eastern Europe). The US atheists have adopted the term in order to signal their opposition to organised religion, however they have to compensate the associated negative feeling of being perceived as immoral, and they compensate it by frequent thinking about ethics, morality and purpose of life.
3) There were several intellectuals in the West who identified themselves as atheists and set the standard for atheist philosophy, where questions about purpose of life are meaningful. (Somebody who knows the writings of e.g. Bertrand Russell better than me should tell whether this isn't sheer nonsense. I can't think about any instance of famous self-proclaimed atheist writing about purpose of life.) On the contrary, Eastern Europe lacks any credible atheist intellectual tradition.
4) The word atheism has simply a sligthly different meaning on different sides of the Iron curtain. The difference has evolved rather randomly, without any specific cause.
Unfortunately I can provide no means of testing the above claims.
Fifteen thousand years ago, our ancestors bred dogs to serve man. In merely 150 centuries, we shaped collies to herd our sheep and pekingese to sit in our emperor's sleeves. Wild wolves can't understand us, but we teach their domesticated counterparts tricks for fun. And, most importantly of all, dogs get emotional pleasure out of serving their master. When my family's terrier runs to the kennel, she does so with blissful, self-reinforcing obedience.
When I hear amateur philosophers ponder the meaning of life, I worry humans suffer from the same embarrassing shortcoming.
It's not enough to find a meaningful cause. These monkeys want to look in the stars and see their lives' purpose described in explicit detail. They expect to comb through ancient writings and suddenly discover an edict reading "the meaning of life is to collect as many paperclips as possible" and then happily go about their lives as imperfect, yet fulfilled paperclip maximizers.
I'd expect us to shout "life is without mandated meaning!" with lungs full of joy. There are no rules we have to follow, only the consequences we choose for us and our fellow humans. Huzzah!
But most humans want nothing more than to surrender to a powerful force. See Augustine's conception of freedom, the definition of the word Islam, or Popper's "The Open Society and Its Enemies." When they can't find one overwhelming enough, they furrow their brow and declare with frustration that life has no meaning.
This is part denunciation and part confession. At times, I've felt the same way. I worry man is a domesticated species.
I can think of several possible explanations:
1. Evo Psych
Our instincts were formed in an ancient time when not knowing the social norms and kow-towing to the political leaders resulted in literal and/or genetic extinction. Perhaps altruistic humans who served causes other than our own were more likely to survive Savannah politics.
2. Signaling
Perhaps we want to signal our capability to put our nose to the grindstone and work for your great cause. Hire me!
3. Memetic Hijacking
Growing up, I was often told to publicly proclaim things like "Lord, I am not worthy to receive you." Perhaps spending years on my knees weakened my ability to choose and complete my own goals.
4. Misplaced Life Dissatisfaction
Perhaps it's easier for an unemployed loser to lament the meaninglessness of life than to actually fix his problems.
The first theory seems plausible. Humans choke to avoid looking too good and standing out from the pack. Our history is full of bows, genuflects and salutes for genocidal a-holes and early death for the noble rebels.
The second seems less likely. Most similar signaling makes people appear as happy, productive workers, not miserable, tortured artists.
The third and fourth explanations fit well with my experiences. My existential angst didn't fade until I purged my brain's religious cobwebs and started improving my life. These things happened at about the same time, so I can't tell whether three or four fits better.
I'd welcome anecdotes in the comments, especially from people raised in a secular environment. If you don't grow up expecting the universe to have meaning, are you ever dissappointed to find it is meaningless?
But no matter the cause, "What is the meaning of life?" is a question that should be dissolved on sight. It reduces humanity to blinding subservience and is an enemy to our instrumental rationality.
Building instrumental rationality may not be the reason why we're on this planet, but it it is the reason we're on this website.