Reddit mentions of The Vision of Eden: Animal Welfare and Vegetarianism in Jewish Law and Mysticism

> About number three: to me it's quite obvious animal abuse was rampant before the flood : otherwise there wouldn't be a Noahide commandment specifically against it.

I'm not sure how that follows, but either way our own supposition is insufficient to determine our personal conduct. We need to conduct ourselves through the lens of halacha and mesorah.

Nobody is saying you have to eat meat - although there is a very strong case to be made that you should on Shabbos and Yomim Tovim, and go and ask any mekubal about eating fish at each Shabbos meal. Furthermore, veganism is explicitly not possible in a Torah-observant lifestyle. You need tefilin, mezuzos, and Torah scrolls. I guess in theory you could just not wear any garments that require tzitzis, but that would be inadvisable, to say the least.

In the end, veganism and even vegetarianism are not Torah values, and while this doesn't exclude them from permissibility, it does mean you can't let your desire to be vegan or vegetarian override your Torah observance.

For a sincere (and relatively pro-vegetarian) look at vegetarianism and animal welfare from a Jewish perspective, please see The Vision of Eden by R' Dovid Sears, who is himself a devoted Breslover chosid.

As for whether there will be sacrifices in the third Temple, see Rambam's M"T Hilchos Melachim 11:1, which is very clear. Perhaps your confusion is arising from the fact that he wrote elsewhere that the reason we offer sacrifices was only because other nations did as well, so we were commanded in a way that was what we were used to - but the source for this is a sefer which Rabbenu explicitly forbid us to study, so I don't think too much stock should be put there.

It does seem that Rav Kook wrote in one place that there would be no animal sacrifices in the restored Temple, but he writes elsewhere that the more correct view is the one in accordance with halacha as per the Rambam.