Everything in life is suppose to be done for the glory of God. Is that not Christian teaching?
Okay, I didn’t word that last bit quite right. I think everything done right and well is supposed to give glory to God. I just thought that the comment which I am here paraphrasing (something like if a person kept a pet solely for the glory of God, and not for personal enjoyment, it would be okay) is put rather oddly.
Most people who keep plants as ornamentals, or keep a pretty lawn, do so because they enjoy it. It pleases them. Nothing wrong with that. If most people keep a pet because they take pleasure in it, nothing wrong with that either.
And as someone pointed out- pet food is made with wastes from the slaughterhouse industry- which employs people. And I do think it’s morally wrong to kill an animal and not make use of as much of its body as we can. Most people will not be eating animal digest.
This is kind of like the argument that livestock use up the world’s natural resources that people need. Last I’ve seen, much of the land is not tillable, and only forages will grow decently on it. I’ve not noticed people eating grass or cornstalks, but cattle and sheep can easily convert these to meat, milk, hides, wool, and other things that we can use.
You can keep a pet. You can buy a decent quality food for that pet, get it vaccinated, and keep it free from parasites and disease. You can let it sleep on your bed if you want. There is no sin in this. You have no idea how many people I help feed and clothe and keep a roof over their heads, by purchasing things that I need- the farmer, the vet, the fencing contractor, the equipment manufactorers, the pharm companies, the slaughterhouse, the grocer, the feed elevator, etc.
None of this is stops me in any way from helping those in need, either.
I do not see what you hope to gain from trying to prove that keeping a pet in many instances is a venial sin. I have found it stated nowhere. Until you can provide evidence that it is, your position is not very compelling.