>>So is there ever any way to know when "the mass market are morons" means what it says literally or when it's a stand-in for "most people aren't agreeing with my strongly held beliefs".

Absolutely there is. We have a measuring stick with which we can measure the validity of one's beliefs: empirical evidence.

If you believe X, and scientists say we have sufficient empirical evidence that confirms that belief, and the mass market doesn't believe X, that makes the mass market a bunch of morons. This is inarguable.