I think being indifferent to the suffering you cause on those around you is a moral failing. You said yourself you aim to treat people how you want to be treated, do you not care if those around you inflict suffering on you? I don't see how indifference to suffering can be universalised.
Edit: didn't see your edit before posting, I still don't think you've justified why the unnecessary killing/causing suffering of a person and animal are different. Your argument seems very circular on this, killing humans and animals are different because they are different.
i don’t know what it’s like to be a chicken or a pig
But you do know what it's like to suffer. And you know pigs, chickens, and other farm animals can suffer. Does that not count for anything? Or do you not consider suffering to be an inheriently bad thing?
OK, so this is literally an appeal to nature. I seriously don't see why behaviour should get a free pass just because it's 'natural,' except the very natural phenomenon of humans killing each other.
living things are in competition and killing is a matter of course. it is natural.
And?
i think a special case must be made against killings. among humans, there are many (distinct) arguments against killing. among the ones i’ve heard, the ones which would also apply to animals are not ones that i personally believe.
What do you believe? From what I've been able to gather from your replies to me and others, you put hold the following two beliefs:
That 'human' is a distinct category of being that makes us the only thing worthy of moral consideration;
That the practice of killing animals is so widespread, so normalised, that it must be morally OK, because if it were wrong, we wouldn't practice it so widely;
Just because they're incapable of being moral agents, i.e. capable of understanding why murder is wrong, doesn't make it OK to murder them. A toddler would happily push you off a cliff, but that doesn't give you the right to push toddlers off cliffs.
It's genuinely amazing how Americas can be so blazé about what's like half the length of my entire country.