"taking in as much protein as you can use...no one would dispute"
And neither do I! The issue is when you say "carbs are evil" because you need that space for protein, but you haven't determinied a threshold!
I did NS and gained muscle and lost very fast and trained pretty reasonably heavy volume...and I was fine!
Nobody says carbs are evil....that's just silly. There is no single protein threshold, it is different for everyone. I can maintain with 200 grams per day. Some people need more, some people need less.
So 800 calories of my diet has to be protein. fat and carbs must split the rest. To eat that much protein and get your essential fats, you are going to need at least 200 calories from fat, if not more. To keep yourself from being hungry, you definitely need more fat, as it is very filling. So lets say I keep fat down to 50 grams, that's 1250 for fat and protein. That means at 1500 calories, I can only eat 62.5 carbs.
Now in reality, I would be absolutely starving on that. I'd also be completely lethargic and unable to exercise at all.
NS may have been ok for you. It is not for most people. You are not like most people. Your body is on one end of the bell curve. Most people are not like that.
It's the same thing with me, I'm on the other end. I can't cheat on the diet...EVER. I can't eat any white bread or rice, or pasta at all ever. Not one single doughnut, no pizza, not one single french fry. NONE. Even oatmeal and Kashi cereal has to be during bulks only and in small portions.
However I don't tell people that's what they have to do to lose weight. Most people are not like me. I have to do that to keep from getting fat. Most people do not. So I don't tell people to be as strict as me because it is not necessary.
So the advice I give is tailored to the majority of people. Unless of course I am speaking to one specific person about their unique situation. If you are one of the lucky few who can just eat less and get thin, great. Enjoy it, most people aren't so lucky.