Ethics is completely subjective. Slaughter isn't for me, but there are other ethical axioms that lead to rational support of the practice. It is not inherently bad.
You cannot sway people's opinions by starting with complete disregard for their opinions, or without a thorough understanding of your own rationale.
I don't agree at all that Ethics is completely subjective. You say that like it's an uncontroversial fact. Just restating It is not inherently bad doesn't add anything, unless you're trying to say Nothing is inherently bad. Whatever inherently means in that sense. I think your last sentence is saying I have complete disregard for your opinions? I don't think anyone has a 'thorough understanding' of their 'rationale', whatever that means exactly.
I get a very strong passive/aggressive vibe from you, like you have no idea how hostile you sound. I really don't like engaging with it, so I'll stop now. Good luck.
"Fooling myself" meaning not agreeing with your opinions? That's not a nice or useful way to talk to people. "We're all just organisms" - I hear that and I think "ah, next comes the faulty argument that was a premise of".
What's wrong with men eating fish. Ah, good question. I don't think you're really asking it, it's rhetorical. But there's a serious vegan/vegetarian literature (I mean, in ethics, written by philosophers) if you really want to learn about the subject. I don't think me talking about that here will be any use to anyone, human or fish.