Earlier quoted context omitted.
This seems the opposite of what I'm asking. I am not asking how biological processes can be modeled by silicon based computers, I am asking in the general sense how one cannot say that biological machines compute just as silicon based computers do.
In that vein you can also ask lots of similar things, as in, why we're not refrigerators, or washing machines, or any other inanimate objects which carry out some mechanical-related stuff. Trying to come up with a compelling reason for why we're not "biological computers" (and this "trying" in itself is half-giving away of one's point in this types of discussions) would involve long discussions going all the way back…
This is part of why I don't see any compelling evidence why we are not biological computers, much as it pains people to admit so.