Why be de-baptised??

At this link is an article about a man requesting the recording of his 'de-baptism' at an Anglican church. I intend no disrespect to the individual, but the interest in the group encouraging this (British National Secular Society) seems to me a contradiction. What concerns an atheist about this record? Do they fear that God might let them in to heaven on accident?? or, if not God...then are they concerned about the other atheists teasing them for the records existence? It puzzles me. Now I'm not confused that there is an organization profiting from the sales of certificates of "de-baptism," just that atheists are buying them.