I escaped the Reddit regime a little while ago. I consider myself a marxist-leninist-MZT. Vegetarian and vegan for a few years. I've a lot of thoughts on how marxism and veganism are connected. Never wrote them down. I'd like to start smth like a club for marxist vegans to develop our own proletarian theory. Most vegan theory I found is either openly bourgeois (Francione is a literal TERF) or revisionist (anti-China, anarchist, libertarian). How about fixing this?
We ate meat before capitalism was a concept and we did it since the cave times for hundreds of thousands of years and it didn't destroy humanity. You cannot delete carnivores from the planet or change the diet omnivores. It's nothing to climate when compared with fossil fuels coal, oil and gas, which guess what are also used to transport certain plants from other countries and thus wrosening the climate.
We'll fish and consume livestock and eggs regularly as we did always unless meat starts getting cloned which as you said, is not possible currently, simple as.