While Atkins was outspoken and uncompromising, and certainly wasn't the first to discover that lo-carb was the most effective way to lose weight, he was the first one to buck the then fairly recent dogma (in the 60s/70s) that dietary fat caused heart disease.

This was why he was pilloried... here was a cardiologist telling the world that you could consume fat without risking long-term heart health. The contrast here is that Bernstein was a layman when he theorised about lo-fat/lo-carb. His stature in the medical community was non-existent... he came into the game later, in a much less intrusive way.