I've done some 'digging' on this ardipithecus and it seems that when the scientific papers on it first appeared it was reported as an arboreal ape that might or might not be a representative of the last common ancestor (LCA) humans and chimps share. But no mention was made of it being a habitually upright walker. Why the change£
I also found out that this Owen Lovejoy guy has been advocating this reduced canines/sexual selection idea (as an alternative to the savannah hypothesis as an explanation for bipedality) for about thirty years and that it has not gained many followers among his peers.
Well suppose the guy learned of a new fossil discovery of an arboreal ape (and therefore not living on a savannah) with leanings toward the LCA. If only he could make it out to be a biped then he could prove all of his competition wrong about the origins of bipedality and become the 'top dog' in his profession.
Just a thought.