I don't think it's morally wrong. And this not for any convincing argument, but because I just axiomatically don't value non-human lives. This isn't one of the arguments you addressed because I don't justify this by saying that they have inferior intelligence or are less conscious since that lands us in even more moral entanglements where it may be alright to kill certain humans.
This means that killing animals, causing them pain, etc. is not a problem to me.
I'm not necessarily sure about this viewpoint, but I'd like to see an argument against this. The only convincing argument I've seen for vegetarianism is that it'll conserve resources, which isn't relevant here.
“These are my principles; if you don’t like them, I have others.” – Groucho Marx
