The content of the links didn't seem relevant to the objection I offered. Perhaps that's incorrect, but you didn't make the case.
>Doing logic is doing metaphysics. Suppose 1+1=2 for addable numbers... that if you have 1 orange, and you add 1 more orange, then you'll have 2 oranges.
I could object to doing math being an instance of metaphysics, but setting that aside, the issue is that the connection between logic and metaphysics is the "mostly unobjectionable" subset of metaphysics that I mentioned previously. So again, you can't substantiate the objectionable parts with arguments that only apply to the unobjectionable parts.
>An ontologist in today's postmodern world surely knows that the (inherently mathematical!) structures that they are building and studying are created, not discovered; subjective, not objective; narratives, not truths.
Here you seem to be admitting that metaphysics is unsubstantive! Metaphysics purports to discover what exists, not subjective notions of preferred taxonomies. But it is precisely the charge that nothing objective is being discovered that underpins the argument against metaphysics.
Now I understand why you see a close connection between what a programmer does and what the metaphysician does: they're both theorizing about contingent domains of inquiry, with no external objective facts at stake. But now I don't get why you object to saying metaphysics is unsubstantive.