So you do a thing that almost no consumers do? Interesting question for finding out philosophical underpinnings of someone’s beliefs/opinions, but at best tangential and at worst verging on sophistry when discussing practical matters. This is not an accusation, just an observation.

But to attempt an answer: for example, I have rescued pet cats. If I find some arts and crafts use for the plentiful fur I “acquire” when I groom them, no big deal. If I make a commercial enterprise out of this and seek to maximize my profits at the expense of their well-being, that’s bad. There are gradations in between that are bad as well — ones that can easily occur for backyard farm animals, where their welfare and enrichment are very low on the totem pole. Especially if you are slaughtering, which obviously places their welfare very low on the totem pole. I’m avoiding the environmental aspect because it’s inarguably increasing GHG emissions compared to what was originally suggested.

But again, irrelevant for arguments about ideal supermarket habits.