You have already received your reply. Users are free to mess with their privacy and money. The client should not recommend them to do so, but if they nonetheless want to create dust outputs, they are free to do so. In the given transaction, it is clear that this was a conscious choice made by the user.
Using a different derivation path for the change output didn't stop those Whirlpool addresses from being linked together.
... yes? That's because spending your received coins and change together is generally considered a feature?
Furthermore, I showed the proof of how I linked postmix Whirlpool outputs to the premix transaction that generated it, which no one ever addressed at all
You showed proof of a Whirlpool user consolidating the many post-mix outputs into one, which agrees with my initial statement that the user is free to mess up with their privacy. If you use Whirlpool in Sparrow wallet, trying to consolidating all these will warn you that it will appear as a self-transfer, and instead will suggest you into adding a mix partner.