Quantum Mechanics: established fact?

I do not hold to the Big Bang theory, therefore I am constantly arguing
with various BB advocates on the internet.

When I say "the BB is incoherent, if the singularity exploded, there
must be a reason..."

they inevitably respond with

"no, Heissenberg's Principle of Uncertainty in quantum mechanics proves
that events can occur without cause, such as virtual particles which
appear out of nothing, so the causeless expansion of the BB is not
incoherent."
===============

My problem with QM at this point is it's refusal to entertain the
otherwise trusty hypothesis that the event occured due to a cause, but
one which we presently cannot detect. Doesn't this popular position in
QM, when carried to it's logical conclusion, make the ridiculous claim
that no matter what discoveries we might make at any time in the
future, we will NEVER be able to find the cause of a virtual particle
appearing, for example, because it's appearence was in fact,
causeless." ?

If Quantum Theorists are good scientists, then shouldn't we expect them
to abide by the time-honored rule that no scientific discovery results
in established absolute facts? If so, then why do BB theorists,
particularly of the Christian sort, act as if "something from nothing"
and "causless events" were beyond rebuttal?

But if we all must adhere to the truth that no scientific advancement
can result in absolute knowledge, but that science is a self-correcting
enterprise, and that what we accept today as a good theory, might be
tossed out the window tomorrow, then why do most BB supporters abandon
this objectivity and rely on current QT as if it was as factual as the
sun on a cloudless day at noon?

.