Atheist - // Pix. It seems to be a common trend here to use acronyms and private jargon to signal to your like-minded chums what you are, whilst confusing ordinary people who are looking for rational discussions. TROB; ROB; EUSSR; Beep Beep Cee; Oh I've lost the will to continue... //
You may be over-thinking this somewhat - I think acronyms are merely shorthand, a byproduct of the texting / social media generation, rather than signals to others that they all belong to an exclusive club.
They are abbreviations, not Masonic handshakes!