Those are very different corners of philosophy. Things can be epistomogically unprovable, but at the same time ethically relevant. Put another way, your count

Those are very different corners of philosophy. Things can be epistomogically unprovable, but at the same time ethically relevant. Put another way, your counterargument applies equally to genocide as it does to octopus intelligence. That doesn't mean we should proceed as if genocide is ethically neutral.