I don't think any reviewer should have a responsibility to justify in detail why they're not accepting a PR, or why they're choosing to spend more time to review one and not another.
I mean, heck, it's going to happen right - a PR from sipa vs a PR from Joe Bloggs.
I think your point about the analogy isn't as clear as all that; the analogy would be more with setting policy and less with what constitutes a valid transaction (that's more, does the syntax of the document even satisfy the definition of a BIP).
If the problem with AI drafts were *only* volume we wouldn't be having the same discussion, nor using terms like slop.