I'm looking at this from leftist principles, not vegan principles, due to the post title conflating the two. To answer your question, I personally only permit spiders and humans in my house and the practical ability to evacuate would affect what I could save other than myself from a fire. I understand the energy efficiency from consuming lower in the food chain, I'm not disputing that. I am offering a genuine alternative in lab grown meat that would avoid both. I'm saying that we as a society could do better, I'm not strawmanning saying you must be perfect to be a true vegan, or that makes your choices not good enough. Each person reducing meat consumption does add up to real benefits, and I'd agree we should abolish cattle industry subsidies, ag-gag laws, and restrict factory farming, common goals for leftists and vegans. But all that doesn't mean that it's necessary, as OP's title suggests, to be vegan to be leftist or vice versa.