Your initial point is that "most people think eating meat is fine, so it's fine". I doubt that's binding your morality, as if suddenly 50.1% of people were against eating meat, you wouldn't then swap to veganism. You're asserting that if the majority think something is morally permissible, then it should be. Which would make Hitler's reign (who was very popular in Germany at the time) morally permissible. Also I'm not trying to legitimise slavers, and you know that, don't strawman.

"People have been eating meat since before people were people". That's either an appeal to nature or an appeal to tradition. First, nature. Just because animals eat meat, doesn't mean we should. Animals eat meat out of necessity, which makes it morally permissible. We do not need to do that. Furthermore, animals murder and rape, surely you don't find this nature permissible? As for appealing to tradition, that argument could be used to justify any number of problematic issues. "Gas companies have been polluting since time immemorial!" "Men have been marrying 13 year Olds since the 40s!", it's a broken argument without validity.

You keep saying that I haven't justified the assertion that it is wrong to cause harm to sentient beings for pleasure. Rather, it is your responsibility to assert that the harm IS justified. YOU'RE the one causing harm, YOU'RE the one who needs to justify it. Currently your justifications include "because we just do", "because we always have" and "because it's not wrong". Those are extremely poor reasons to harm others.

A valid argument to kill and eat another sentient being could be "because it's necessary for me to live". That would be valid. "Because you haven't convinced me not to" is not. You wouldn't accept that excuse from a murderer.

When did we establish that it's not about pain? I don't want to cause animals pain. Vegetarianism DOES include death. Male chicks can't produce eggs, so are ground up in a machine shortly after hatching. Male cows do not produce dairy, and must be killed as soon as financially possible. I say pain and death, because that's what meat eating causes? Sorry I didn't understand your paragraph on this one.

As for "respecting other cultures", you wouldn't accept that as reasoning for me to kill and eat people would you? If a culture/people require the killing and eating of animals for their own survival, it is permissible. But as for western culutures, it is not necessary, and thus is only done for pleasure. Which is not a valid reason for killing something (as we agreed upon in the dog stomping example).

Like I've said here, I'd love to not be vegan. I loved eating meat, I grew up on a farm in rural New Zealand. If you can come up with a good reason to kill and eat animals, I'd LOVE to hear it. But if the argument "you haven't convinced me not to" doesn't justify the murder of humans, why would it justify killing animals, who also feel pain, sadness, grief and fear?