These kinds of studies don’t prove anything, in any kind of way. Relying on people to remember what they eat is not scientific in the least.
It’s also not scientific to just assume it’s the meat, when there are a lot of other commonalities among what people eat.
Especially when it’s already known and shown that carbohydrates and sugars are what cause heart disease and diabetes.
So much so, that even The American Diabetes association advocates High fat, low carbohydrate diets.
What would actually determine if meat is healthy or not, would be to track people on all meat diets.
This is literally the only way to remove (most) confounding factors.