Well the real question here is, what benefits occur to society from "meat abstinence". And that's really what we're talking about, abstinence, and not some kind of societal impact that is relevant in any real way. For instance, if you stop having sex, does this impact anyone in the world other than those who wanted to have sex with you? Not really, someone will find someone else to have sex with, just as the meat will find someone else on the market to eat it. The only real difference a meat abstainer, which is the real wording for an ethical vegetarian, can make is commerical. Less people eating meat impacts the economy in some small way, but with population growth or foreign markets, this is all negligable anyway. So meat abstinence should be a personal choice, but never assumed a moral one that is helping a greater good.
Furthermore, if one IS a promoter of the vegetarian lifestyle through ethical abstinence, what of collateral damages that come with the existence of mankind? Living, breathing, interacting within a society is by the very nature of existence, displacing the natural environment and habitats of creatures that would otherwise live there. But have you not, as a creature as well, have a right to occupy that space? Let us tackle a less abstract direction, and speak to the production of alternative foods, that of farm-produced corn, lettuce, soybeans, all those things vegetarians love to eat. The petrochemical industry is inherent in this type of food production, whether it be through farm machinery, pesticides, or whatnot. Organic you say? One hand must still wash the other, you need animal fertilizer to grow crops, thus one must procure the excrement from cattle or various animals being slaughtered for market to produce the crops.
This is why ethanol at the moment is not a viable fuel alternative, as it takes so many petroleum products to produce the altenative fuel source that it makes the alternative a rather negligable reduction in emissions. To understand ethical vegetarianism, one must really understand where all of your food sources come from, a near impossibility, and even then if you do know where your food comes from, how can one possibly claim to lead an ethical lifestyle, or put more to the point, a more ethical lifestyle than those whom the vegetarian obviously disapproves of? It is a difficult and slippery slope to traverse, as claiming a clear ethical advantage over other people is something for pure subjectivity. Who is to say that the products bought by an ethical vegetarian do not in some way create more harm to animals than merely eating them on your dinner plate? Who is to say that animals are not routinely killed, as we know they are, in crops harvest, cultivation, and preservation during growth?
