Whether gravity is a "force" or actually a condition of geometry might be an unanswerable question - the geometric picture accords extremely well with the rather elegant math, which makes little sense otherwise, but then again it's possible that gravity as geometry is just a convenient picture.
Either way of looking at gravity, though, predicts that gravity propagates at the speed of light, and that if it doesn't, it has to propagate more slowly. In the quote you just used, I was referring to your claim (one post up) which seemed to say that if gravity is geometric, then it would propagate instantaneously. Nonsense. Theoretical consistency with special relativity - which is a very, very well-tested theory - demands that it be unable to propagate faster than light, lest we get into hairy issues of causality. Theoretical consistency with quantum field theory - another very well-tested theory - demands that no force travel faster than light. And on top of being theoretically consistent with well-established theories (which is very important), the propagation speed has been measured to be within a small percentage of the speed of light by direct experiment.