I would like to see what "ELSE" these 2400 middle aged men were eating with the high protein. Keto diets (properly followed) for instance (Low Carb high protein with the correct supplements omegas and vitamins and healthy fats) actually decreases your risk significantly so saying it's the protein causing this high risk is probably false. High protein with high carbohydrate diet essentially fills our body with glucose and empty calories. This raises blood sugar levels, raises the risk of coronary heart disease, elevates triglyceride levels (also increases the risk of heart attacks) and so much more.
I believe the culprit in today's diet is the addiction to carbohydrates. Lets face it we evolved from a hunter gather lifestyle just a few thousand years ago where our diets were all natural plants and animals, now look at what we eat! Check out the netflix documentary for KETO in Australia and see what happened to the aboriginals who now eat mostly carbs and all the heart/diabetic issues they ALL have and what life was like in previous generations where everyone was fit and strong and no health issues. They are dying from carbs literally.
I hate these studies that claim stuff like this, it's just news for them (Something to post in hopes people read it so they can cash in on the traffic)