Trueadonis is oversimplifying fat loss.
I imagine caloric deficit as a vacuum attached to few different holes - muscles, fat and so on. When on enough drugs we can pretty much assume hole with "muscles" is blocked. Yet it doesn't take just vacuum to get every piece of fat.
If you do not open the hole with fat enough you will not get that fat at desired rate. Concept of caloric deficiency is stupid because it assumes you will burn same amount of energy every day. But if you eat 2000 calories and for whatever you do throughout the day, you need 3000 calories and you're not able to burn 1000 calories of from your own fat storage for whatever reason then you will simply NOT be able to do whatever you do throughout the day. You will be tired earlier in the workout, your batteries will simply go off.
Concept that macronutients are irrelevant and "deficiency" is enough is simply not true for that reason. There are proportions which will give enable you to burn MORE fat.
Also IIFYM is oversimplification but it's close enough. Micronutients and fibre are also crucial for fat loss.
At some point into the diet I imagine that you have to be very cautious because you eat so few calories that if you change your rice to gummy bears you might not get enough fibre or enough minerals/vitamins which will impair your ability to loose fat.
tl;dr: Adonis assumes that caloric deficiency is sufficient because he falsely assumes that if you eat, say, 2000 calories from whatever you will always have enough energy to burn 2000+X calories throghout the day.