Protestant vs. Catholic atheism

In Northern Ireland, ethnic animosities have been cloaked in religious terms, with Ulster-Scots taking the Protestant mantle and Irish taking the Catholic one. This means that atheists are necessarily in a bit of a tricky position.

There is an Irish joke regarding this situation, a variant of which was notably repeated by Richard Dawkins in his book, The God Delusion:

A journalist, researching for an article on the complex political situation in Northern Ireland, was in a pub in a war-torn area of Belfast. One of his potential informants leaned over his pint of Guinness and suspiciously cross-examined the journalist: "Are you a Catholic or a Protestant?" the Irishman asked.

"Neither," replied the journalist; "I'm an atheist."

The Irishman, not content with this answer, put a further question: "Ah, but are you a Catholic atheist or a Protestant atheist?"

In Protestant atheism
Some "Catholic atheists" have used this humorous distinction to highlight a perceived admixture of class snobbery or Protestant anti-Catholic canards with atheist rhetoric.

For example, the self-described "Catholic atheist" Michael Fitzpatrick takes Richard Dawkins to task for using his atheism to cloak disdain for the masses who are doped up on their chosen opiate, religion. Padraig Reidy, commenting on the state visit of Pope Benedict XVI to the U.K., pointed out some parallels between the rhetoric of some of the groups opposing his visit and the ramblings of Ian Paisley, and also stated that the Church hierarchy could be much more easily rattled by people who knew the religion.

In Catholic atheism
"Protestant atheists" have been comparatively silent on this topic, but Dr. Fitzpatrick cited a respect for the cultural "living tradition" embodied by Catholic institutions as part of the Catholic atheist mindset. This is, understandably, something a Protestant would show less respect for, perhaps dismissing it as "incense and chanting."

As a general phenomenon
This is just one instance of the broader idea that there is no clear-cut distinction between religion and culture; indeed, the words "culture" and "cult" both have their roots in the Latin cultus. Hence, an atheist within some theistic cultural zeitgeist (with the possible exception of those who adopt a completely new world-view, such as communism) will continue in most of the cultural practices of their nation, which outsiders might attribute to the nation's religion.