...it strikes me as another example of smug atheists trying way too hard to assert their nonbelief.
But if you read the TIME article as well as the certificate itself, the explicit intent of the NSS is to make the church's census count of church members more accurate, in part to limit their proportion of political sway. That doesn't strike me as "smug" or trying "way too hard," but rather a defense against dishonest political tricks.
UCrawford: …and it’s more likely to just polarize religious opinion against atheists because they’ll see it as us profaning their rituals…which it kind of is.
... But look at the ritual of baptism. Why do it? Because you fear that if you don’t engage in this strange rite, you will actually burn forever, even after you die!! And, you teach children that this is so, cruelly instilling fear in them. (Your friend who died in the car accident was only five years old, but since he wasn’t baptized, he is now being cooked and will be forever! Not only will little Jimmy not be able to play with you, he is right now screaming in agony! But God loves you.) Do you really, really think that such a ritual needs to be ridiculed to be any more profane?
I'm an American and I wasn't raised in any church. I voluntarily was baptized on my 18th birthday, so the particulars of these certificates don't apply to me. Even if they did, I wouldn't do it even if it were free, for the same reason I don't vote: I reject the underlying premise that our rights are subject to the outcome of polls or censuses. If 99% of the population joined a church, that still wouldn't give them the authority over the lives of the other 1%.