it feels like we're forgetting the point of the original post. To re-iterate, this thread is about exploring selective discrimination.

Okay, let's start over. This is from the top of the post:

Why is it fine to advocate against harming some animals but not all?

If you advocate against harming all animals, I become confused. Many of the phyla in the animal kingdom contain animals that are microscopic. Many of them have primitive or no nervous systems.

If I destroy a stapler, I am not hurting anything. I think it is okay to "selectively discriminate" against my own stapler.

I think it is okay to destroy microbes; I don't believe I am doing harm. Life is special, and I don't support destroying any form of life for no reason, but I have no problem with destroying something that does not suffer when the species is not threatened.

Your idea about imagining ourselves in the place of an animal is a good one. It takes some imagination, but it does help me recognize that a cat or dog or pig is capable of suffering. I don't want to be a part of that suffering, which is why I have reduced the amount of meat that I consume.

I can't imagine what it is like to be a worm any more than I can imagine being a stapler. A worm wiggles around if you poke it, but I doubt that it experiences suffering. We could investigate based on our understanding of consciousness and pain and look for evidence like nerve endings and cortisol levels. We might be uncertain, and like most things in life we will have to make decisions despite our uncertainty. For my part, I am comfortable eating a scallop, knowing that it does not have a brain.

I am not sure at what point an animal becomes complex enough that I should worry about harming it. In particular, I am concerned about male chicks that are destroyed so their sisters can become egg-laying hens. I would like to know if selectively discriminating against these chicks is more like destroying a microbe or like harming a cow. When I ask you your opinion, you refuse to speak of anything except elephants.

Plenty of animals are violently killed by other animals (even when not necessary for survival)

Can you give me any examples? I'm particularly interested in examples of this happening in the billions of victims.

British house cats kill 275 million animals a year. A typical house cat kills between 30 and 40 animals yearly.

The ten countries with the most pet cats have over 200 million cats. In those countries cats kill over six billion animals each year.

The researchers who performed the study counted only dead animals "brought home" by domestic cats. Wildlife advocates are considerably interested in this issue.