I always felt that argument 1 is a bit hypocritical and not very rational. We kill animals constantly for many reasons - farming even for vegetables requires killing rodents and birds to prevent them eating the crops, we kill rats and other pests in our buildings to keep them from transmitting disease and damaging cables, we regularly kill animals by bumping into them when we drive a car or take a train or a plane, ... And of course, we massively take living space away from animals, leading them to die.

So why stop eating meat, and yet disregard all the other multiple cases in which our technological civilization massively kill animals ? I personally don't think most animals matter from an utilitarian point of view (they have no consciousness), but if they did, "not eating meat" wouldn't be enough, and eating meat from "dump" fish or chicken would be less a violation of ethics than killing "smart" rats for pest control.

Reason 2. would prevent eating factory-farmed meat, but it wouldn't prevent eating meat from less intensive forms of meat producing (or from wild game) which are usually available in supermarkets here in France, but a slightly higher price.

Reason 4. is just false taken in its absolute form - there are several studies showing that eating too much meat (especially processed meat) is harmful, but so far it seems some kind of meat (like chicken) is pretty harmless, and that eating a bit of meat is better health-wise than not eating any.

Reason 3. and 5. could justify eating less meat, but not no meat at all.

So with the available data, I would recommend eating perhaps less meat (for reasons 3., 4., 5.), less of the high-fat processed meat (like bacon) and try to buy food from more "humane" farms (for reasons 2), but not to stop eating meat completely.

To be honest, I never saw how it would be "self evident" that not only there is some "objective reality" out there but that we also have an accurate representation of it. How would we know our representation is accurate? We don't have access to an objective observer, we don't even have access to a non-human observer. Immanuel Kant said, back in the 18th century, that in truth, the "laws of nature" are "laws of human perception [of nature]".

I recently wondered if the idea that our perception of reality is an accurate representation of the underlying objective reality was actually a commonly held idea around here. In Eliezer's short story "Three Worlds Collide", he has the characters say as much, because they assume that the periodic table and mathematics would be the same for every other species. But there is no reason to assume that is true.