Because the "object is rolling without slipping". That means that any point on the objects circumfence that is in contact with the surface on which it is rolling does not move forward of backward on the surface.
(Oh, and saying "the instantaneous speed is 0" is NOT the same as saying "there is no instantaneous speed"!)
Well, I now see that there isn't enough data in the problem to calculate the rotational speed of the point of contact. But, the key idea is that the translational speed and the rotational speed are equal and opposite, leading to a net force of zero.