So all you're talking about is a concept, not an entity at all?The fact that we humans conceptualize such a source, and wish to communicate that concept to others, justifies the existence of the term.
You don't behave as though you think reality is merely conceptual. You breath real air, for example. You think your parents are real, for example. You post on RF, for example.The truth is 'what is'. Reality is what we think 'is', is. Reality is all we have of the truth, and it's ultimately imaginary: it's conceptual.
Those folks sound unfortunate, don't they. Has no one explained the working philosophy of reasoned enquiry and scientific method to them? It's never too late to understand that there are no absolutes and that truth is our best opinion for the time being.A lot of humans fail to recognize this, however, and so believe that their imagined conception of reality is 'what is' ... is the truth. And believing this gives them comfort, and supports their egos when they would otherwise have to face the profound ignorance and vulnerability of their human condition.
Incidentally, what definition of 'truth' do you use?