No the point GP is making is that atheism is a religion (it's not), which is in itself wordplay.
To try to stay on the subject of the article, I find it interesting that it's Protestants who are abandoning their faith which is most of the downward trend in the graphs presented. I find that makes sense as Protestants are generally less dogmatic and more questioning (at least historically they were from my understanding) than their Catholic brethren.
Another way to put it, I feel there are some structural differences between Protestants and Catholics which help to explain the downward trend in one, and less so in the other.
Catholicism is a culturally "thicker" religion, which I suspect is responsible for the trend of lapsed Catholics continuing to describe themselves as Catholic in opinion polls even when effectively Nones. If you operationalized the definition, say by asking "have you been to church in the past week?" you'd probably see more similar trends.
To try to stay on the subject of the article, I find it interesting that it's Protestants who are abandoning their faith which is most of the downward trend in the graphs presented. I find that makes sense as Protestants are generally less dogmatic and more questioning (at least historically they were from my understanding) than their Catholic brethren.
Another way to put it, I feel there are some structural differences between Protestants and Catholics which help to explain the downward trend in one, and less so in the other.
edits: bad grammar