I have always found it irritating that some religious people insist upon the idea that the absence of belief in a god is also a religion. Such an inability to see things from any other frame of reference explains a lot, but it is also hard to counter.
However, thanks to an incisive comment by a user named PsychoKick on, of all places, Fark, I have found the ultimate riposte.
“If athiesm counts as a religion, then ‘not collecting stamps’ counts as a hobby.”
Philosophy lives on on the internet.