Atheism itself is just that negative belief, that theistic religion is irrational, that there's insufficient evidence to justify its theistic premise. But atheists as people and as a group make many more points than that. Otherwise their heads would be practically empty and they wouldn't get much done, right?
Even those atheists who are too busy to think philosophically tend to presuppose certain values and philosophies (such as secular humanism, neoliberalism, pragmatism, philosophical naturalism), all of which would have to be justifiable without recourse to theism.
But I understand the inclination to pretend that atheists have no positive philosophical obligations. It's as Dawkins' bus slogan would have it, “There's probably no God. Now stop worrying and enjoy your life.” I can see you're following that advice, which is fine. It's OK to leave the atheist's positive philosophical labours to others like Dostoevsky, Nietzsche, and (in a much humbler capacity) folks like me who've done a Ph.D. in philosophy and been pondering and writing about this stuff for decades.
Unlike the carefree “new atheists,” the old-school Nietzschean atheists do worry that carefree secularism represents a kind of existential inauthenticity. Don’t forget the nagging little concern that in an indifferent, inhuman, godless material universe, all life projects are ultimately absurd. The trick is to grapple with that implication of atheism and of naturalism with honour and integrity.
Minchin agrees that life is meaningless, given atheism. He says the solution is to stop the futile search for meaning and to fill your life with healthy activities. In other words: ignore the problem and rely on distractions.
Again, I can see the wisdom of that solution, but it’s fit for the anti-philosophical herd. Not everyone’s a thinker. Some are doers. Let the thinkers think and the doers do. Let every flower bloom, for as Psalm 103 says, “The life of mortals is like grass, they flourish like a flower of the field; the wind blows over it and it is gone, and its place remembers it no more.”