1) humans are omnivores not carnivores. This is why we have incisors and molars.
Try eating a purely carnivore diet and see how that affects your health. A complete lack of fibre will quickly lead to constipation to highlight just one issue.
2) the statement that we’re eating less red meat than ever before is laughable. For most of human history meat was a luxury and difficult to procure let alone store. 

 Plant Free MD Podcast, start on episode 1. 

 Well, that meat historically was a luxury is a proven fact. That said if you want to eat only red meat it’s a free choice. Just don’t rewrite history to make your point. You don’t need it.