It sounds a bit like Robert de Niro’s “You talkin’ to me ?”. Both questions succeed, in just four or five words, in leaving no doubt about the speaker’s sense of superiority, his aggressivity and the low opinion he has of the person in front of him. Non-atheists are sometimes less abrasive than atheists (“So you actually believe that the world just happened, without anyone to make it happen, with no meaning or purpose ?”), but the implication in the question, like the title above, is that you have to be pretty stupid to hold such a belief. Many exchanges between believers and non-believers are openly confrontational, attempts to score points with a reductio ad absurdum. They generate friction, heat but little or no light.
It can be malicious fun to participate in such dialogues of the deaf, and entertaining to watch the gladiators go for the jugular. You can even win an argument and leave the opponent bloodied, shamed and ridiculed, which is what many in the audience came for and perhaps paid to watch. The best of the star performers on both sides of public religious debate are careful not to go too far. Outright insults, like obfuscation, are to be eschewed. You may make a serious dent in the opponent’s armor, but you should beware of the ricochet or the boomerang effect, and the danger of turning off the audience in favor of the underdog.
All this reduces the serious question of believing or refusing to believe, to mere rhetoric. Better to base one’s arguments on personal convictions which are the result of unbiased examination of the evidence. What we believe or refuse to believe is not “stuff”. You do unnerstan what I’m talkin’ about, right kiddo ?