The key to a good diet is balance. Too much red meat has equally severe health implications, leading to a higher risk for heart disease, cancer, diabetes, and premature death.[1][2]
Mankind evolved to eat red meat. We developed fire for it. We invented spears and bow hunting for it. It's one of the healthiest foods you can consume, has been part of the human diet for over 2 million years... and besides the noted protein, it contains B12, Zinc, Selenium, Iron, Niacin, B6, Phosphorous and many other valuable nutrients. You can live exclusively off a diet of just red meat and live a long, healthy life. Many tribes do, including the Maasai in Kenya, the Sami in Finland, and the Inuit.
Well if you want to take a retrospective, we also did not consume it every day. We grazed on other things, including veg, fruit and grains, not unlike traditional societies today.
The Inuit don't eat the way they used to, but it was a good deal of fish along with game and berries (ditto for Sami). Their CVD profile has never been reported to be particularly good. Maasai consume mostly milk, and are in a perpetual state of caloric deficit.
We are omnivores. Junk food hacks an instinct to eat dense vegetarian calorie sources. But we will eat anything we can get our hands on, and that seems to start even earlier in the family tree than the hominids.
Meat is a target of opportunity, one that helped us build much larger brains. But it’s not the only thing we’re tuned to eat.
> Mankind evolved to eat red meat. We developed fire for it.
I read somewhere that in some sense minkind devolved to eat red meat. Some gene was damaged, which helped humans to do a marathon activity to track red meat running away (IIRC something to do with an ability of blood to carry oxygen), but humans lost a key enzyme to process fatty acids from red meat. So mankind got more proteins but started to die from heart desease. Probably it was no so bad then because an average lifespan was too short to develop severe symptoms.
Mankind rarely lived beyond 25 until very recently so the long-term effects of high red meat consumption have never been part of the evolutionary equation. There have been numerous long term studies that have found strong links between diseases, esp. heart disease, diabetes, cancer. These diseases take years to manifest normally thus wouldn't have existed then.
Life expectancy being 25 doesn't mean nobody lives past 25. Estimates that low for early humans is skewed by huge infant mortality rates. IIRC living into the 40s or 50s was typical for an early human that survived to adulthood. 60s or 70s not uncommon.
We can't actually tell the age of death of human fossils past the time that wisdom teeth grow in. There's no way of telling whether a fossilized skeleton was 30 at death or 50 at death. Even then, we don't necessarily have a representative sample.
The Sami, as I mentioned, have been studied. They are a tribe of reindeer herders in northern Scandinavia. They eat a diet consisting of almost exclusively reindeer meat. They have lower cancer incidence than Finns (https://onlinelibrary.wiley.com/doi/full/10.1002/ijc.10486).
> They eat a diet consisting of almost exclusively reindeer meat.
Very far from a typical meat diet (quoting from your link):
"The dietary habits of the Sami differ from those of the other Finns. Reindeer meat (low in fat) and fish have been important foodstuffs in the diet of Sami people. Intake of vegetables and fresh fruits has been low, but berries were eaten, especially by the North Sami. Although nowadays dietary habits have become more similar to that of the rest of the population, still more than 90% of male Sami reindeer herders eat reindeer meat at least 3 times a week and almost 50% eat fish at least twice a week. Reindeer meat and fish contain high concentrations of healthy lipids, trace elements (e.g., selenium), minerals and vitamins. Arctic people usually rely on blood, liver or kidneys from animals to obtain adequate nutrition."
All of these types of studies are being debunked: it's not the red meat that's the problem - it's 1) the quality of meat you're eating, and more so 2) the other crap people are eating. The first Carnivore Conference happened last year, and the movement is growing.
Edit to add: Look up Dr. Georgia Ede videos on YouTube for some of this debunking.
[1] https://www.health.harvard.edu/staying-healthy/whats-the-bee...
[2] https://pubmed.ncbi.nlm.nih.gov/26780279/