I agree with you broadly, and despite their abhorrent reputation for sourcing unethical animal products, it does seem that you're right about McDonald's fish. However, on a larger scale, one of the hidden ethical pitfalls is that a lot of wild-caught fish comes from international waters, where there are no regulations whatsoever, or are imported from Asian countries with little to no regard for such things. Japan infamously still allows whaling. The global fishing industry is also rife with modern-day slavery.