This is a great question, Nico. I would love to find something along these lines, too.

A pretty fascinating part of it would have to be the whole Battle Creek Sanitarium nexus in the mid-1800's to early 1900s. There you have existent Protestant obsessions with purity and revulsion towards animality (see Kellogg and Graham equating flesh consumption with sexual lust over and over again, with scary leaps and consequences, advocating fasts and veganism as a way to curb dangerous base desires) coming together with the social movements of the time (temperance, abolitionism, and yes, eugenics), big business (Kellogg and Post eventually give birth these now huge companies by investing grains with timely moral significance) and people of great influence (patients included presidents, celebrities, authors, industrialists, abolitionist leaders, and more.) While one can chuckle at the most egregious examples of wackjobbery found in this movement, you can't ignore the long-lasting effects that it has wrought upon America, its people, and notions about health. (This post has inspired me to delve deeper into this. Plan on picking up this and this book soon...)

Upton Sinclair was also a patient and I don't think one can forget the role his works, as important as they were to bringing attention to the dangers of industrial food production, had in helping spread the red meat=unhealthy/bad/gross equation. Interestingly, I recently came across a quote from him that surprised me in a good way:

Recently a friend called my attention to the late Dr. Salisbury's book, "The Relation of Alimentation to Disease." Dr. Salisbury recommends a diet of broiled beef and hot water as the solution of most of the problems of the human body; and it may be believed that I, who had been a rigid and enthusiastic vegetarian for three or four years, found this a startling idea. However, I make a specialty of keeping an open mind, and I set out to try the Salisbury system. I am sorry to have to say that it seems to be a good one; sorry, because the vegetarian way of life is so obviously the cleaner and more humane and more convenient. But it seems to me that I am able to do more work and harder work with my mind while eating beefsteaks than under any other regime; and while this continues to be the case there will be one less vegetarian in the world.

I certainly take no offense at a contrary position. But "Hugh"'s handle is offensive. Argue your conventional wisdom take on red meat, but simply use your own name, or less sophomoric handle.

I suspect most people have no clear reasoning behind assumptions that red meat is bad. It's just one of those things that 'everyone knows' because other people who didn't know anything told them it was true. Dig a little deeper with your questioning and you will probably get the added statement that red meat if full of saturated fat and that 'everyone knows' that fat and especially saturated fat is bad for you. I do think there is a small percentage of people who really care about the life of the animals themselves, but not many. My guess is that the red meat is bad myth originated somewhere in the saturated fat is bad myth. ANd I think the saturated fat is bad myth originated in part from the corn oil and PUFA oil industry that was attempting (successfully I might add) to block the influx of foreign cooking oils like palm and coconut oils by launching a media campaign declaring the already established oils to be more healthy.

I don't believe there is one concise myth, but several beliefs related to this question. One primary reason is the lipid hypothesis. Another would be the unfortunate way beef is chemically modified and processed, which has some people thinking that it's always a bad food source. Clean eating and moderation is a challenge in the U.S. Also, there are some people who are against the cruelty of animals do to religious or personal beliefs. As I'm sure you've noticed, there is a lot of confusion where food and diets are concerned.

As Mark Sisson puts it:

"Meat is unhealthy; everyone knows it, right? Of course they get the most diseases, the most heart attacks, the most cancer. They can even cite mainstream studies that claim as much, studies that make the front page of every mainstream publication. The latest was the infamous red meat study that seemed to show the more a person consumed red meat, the greater their cancer, heart disease, and total mortality. It makes for a good headline, but it doesn’t mean much. For one thing, it shows correlation, not causation (establishing a causative mechanism would require controlled studies), and for another, it also showed similar connections between mortality and marriage status, smoking, high BMI, lower education, low physical activity levels, and low fruit and vegetable intake. How many of these meat eaters were also eating potatoes fried in rancid vegetable oil, swigging a jumbo Pepsi, and polishing off the meal with a bowl of ice cream?"

source, with links to the studies: http://www.marksdailyapple.com/in-defense-of-meat-eaters/

I'm sorry to go against the party line of this suggestive question, but there is the hypothesis that dietary heme found predominantly in "red meat" could induce carcinogenesis: http://cancerres.aacrjournals.org/content/63/10/2358.full http://carcin.oxfordjournals.org/content/17/3/515.abstract These are just two relevant results I got from Google Scholar, you can search yourself and check out the other related studies. There may also be other factors, such as cooking (cf. polycyclic aromatic hydrocarbons) and other preparation methods, that are not related to the health effects of "red meat" per se.

The claim that this "myth" had its root in the vegetarian or even vegan movements doesn't hold up as it cannot explain why "white meat" and fish are generally regarded as either neutral or beneficial. There are also studies that positively associated "red meat" intake with gastrointestinal cancers, but found no such association with "white meat" and fish (fish may even be protective).

All in all, I tend to agree with the current scientific mainstream that mammal meat does indeed increase overall cancer risk. I am again sorry for offending the prevalent groupthink in here.