There has to be a push off with your foot against the ground/rubber just to initiate the stride. But the question is once the body gets going then how much pushing does there continue to be? Is there a point in the stride where the pushing stops and the body's movement towards the target is driven entirely by momentum? If so, then the foot will be pulled off the rubber. In this case, there is both a push and a pull.
Now, do I know this is for a fact the way it works? No. This is what I think is believed by those who claim the back foot pulls off the rubber. Do I think this is a feasible argument? Yes. The momentum of the stride leg swinging from knee lift to foot strike does generate a lot of momentum. Plus, the back foot usually turns over and drags and it's hard to do any pushing during those actions.