I believe Quinn (is that your name?) has hit upon the main crux of the argument. We could spend any number of aeons discussing what the meta-magical and energetic consequences are or might be, and only truly inspired or accomplished Formal Magicians would really be able to answer that question. However, what she brought up is the question, "Regardless of whether there is more Chaos being created, is it right to use Chaos in any manner?"
Even if you didn't cast the spell yourself, you are still consciously using the powers of Chaos to harm another creature. That is, you are actually benefitting from Chaos and its effects. Sure, it's a protective, but by using such a Bane you are still affecting another with the horrors of Chaos and, thus, propagating the system. Truthfully, it seems to me, if we take it as premise that Chaos in every form is always destructive, wouldn't a Bane vs Chaos charm be just as bad?
If we are to allow Bane charms, which refocus Chaos magics, why not allow other charms which cast Chaos? In neither case would the bearer of the charm actually be casting Chaos, they would merely be releasing energies within the charm cast by another. It seems to me, though they are not exactly the same, the line seems mostly semantic.
And though Red Wizard Peece speaks honestly that one cannot choose what one finds, one can certainly choose not to use such tainted items. After all, though one is not casting Chaos, one is, by omission, allowing it to hurt people.
Master Dramthin Hartsboon
Simple Keeper of the Tainted Grove