Why do theist often drop the letter s when referring to atheists?

[I_am_not_mafia]

The atheists recognizes the multitude and humanizes the opposition.

The atheist dehumanizes the opposition, diminishes their perceived numbers, shoe horns them into one single entity, and emphasizes what the theist perceive to be a common animating wickedness.    It makes both superciliousness and loathing roll more easily off the tongue.

It is much the same as the Nazis propaganda, as well as contemporary neo-Nazi propaganda, refering not to the Jews, but The Jew, when alledging common racial trait justifying the exterminatory antisemetic policies.

This is the most plausible explanation for me. So some theists like GC who reads lots of propaganda picks up the term without realising it.

Sorry I should rephrase that last sentence.

The theist, after reading lots of propaganda will start using the term without realising it.

Ooh ... sneaky linguistic technique!