Gravity, graviton and force

[touqra]

Gravity is seen as an effect of spacetime curvature in GR. Why is it that QM sees gravity as a force like the other three fundamentals: Strong, weak and EM.
If this is so, why bother envisaging on the graviton, when gravity is due to spacetime curvature and not force via virtual particles.

[selfAdjoint]

Quantum physicists sincerely believe that the world is fundamantally quantum. Thus they can't accept the complicated classical physics of GR, though successful, as anything but a limiting case of some deeper quantum reality. Thus they adopt the mirror image of Einstein's belief that quantum mechanics, though successful, was incomplete and only a limiting case of some deeper classical reality. Go figure.