Your argumment is a post hoc fallacy. Even granting that redemption came because Christ became man like us (a point open to debate within Christianity), it does not follow (thus the post hoc fallacy) that Christ had to be related to all of creation in a similar manner in order to redeem it.
The simple explanation is that creation fell when man fell, and that creation is redeemed when man is redeemed. This makes perfect theological sense if man is the special creation for which the world was made, and which man was given dominion and lordship over.
It seems to me that the primary focus of theistic evolution is to treat the theory of evolution (and all science in general) as the ruler of absolute truth to which the Bible must be stretched to fit rather than have scripture be the ruler by which all other things are measured.
But why would the world fall when man fall, if man did not come from the world?