Rational Thought

Rational thought to provide an acceptable explanation of any situation is affected by what is logical or rational. But to whom? Who decides what is acceptable? What is 'rational'? The idea of a conspiracy theory and the like are rejected for no reason other than they don't conform to the consensus opinion. No counter arguments, but rejected nonetheless. Nothing more than faith in some answer that has been accepted. Even if there is no answer or explanation, rejection can still occur for no good reason.

Who proposed the answer? Why should this be any more correct than any other?