[subungual]

I've not really encountered the idea that it's unnatural exploitation, to be honest, and I completely agree with your point there. The core ethical argument that I generally see presented for veganism is that once you've advanced past the point of requiring animal products to live a healthy life, consuming them becomes entirely a matter of convenience, taste, and preference. The argument follows, then, that it may not be ethical to subject animals to the realities of modern husbandry simply on account of these reasons.

The question of whether abuse is inherent is largely academic at this point. The fact of the matter is that almost all of the animal products we consume are the result of optimized industrial processes that result in shortened, low-quality lives for those put through them. Whether an animal could, under the right circumstances, be humanely raised for resource extraction or slaughter doesn't really apply in modern consumption.