Perhaps it was some Freudian type of slip, but you mentioned the argument...something like "there'll always be debates between atheists and christians"...as if there are no other religions at all. People say "happy holidays" because SEVERAL religions observe holidays during December (many of which have ALWAYS celebrated during this time of year instead of replacing more ancient, non-christian holidays as christianity did).

Just so you know, most atheists I know have arguments with all "god" based religions.