Actually, if you look at the meaning of theory, it is a theory. What the "Troothers" have is an unsubstantiated hypothesis. But the words "conspiracy hypothesizers" just doesn't roll off the tongue very well. So even calling them theorists is an error.
So in my previous post replace "theorists" with "hypothesizers". Then it should be more accurate, though I do reserve the right to continue pondering the semantics and making further corrections to my position as we go.
No, they're theorists. This whole thing is an exercise in colloquialism.