Put simply, very high protein diets (>3.3 g/kg or 1.5 g/lb) are not conducive to everyone's objectives. These diets provide satiety and increase fullness, which can be detrimental to increasing body size. This is because increasing the % of macronutrients one consumes as protein necessarily means reducing the % of carbohydrates (and fats, which should be maintained at an absolutely basal (or >) 20 - 40 g/day to support endocrine function; though, indeed, exogenous androgen serves this function). Very high protein diets are also not conducive to bodybuilding training as typified by moderately high contraction grouping (8 - 15 reps +/-) coupled with short rest intervals (<= 1.5 min) to enhance metabolic factors (including metabolite accumulation), because these sorts of resistance training efforts are glycolytic (rely on glycolysis; or the catabolism of glucose, to perform work).
Skip these next paragraphs unless you are interested in the metabolic processes involved (I saw questions early on in this thread):
Very high protein diets do tend to, on a per-calorie basis, deposit relatively (to the other macronutrients) less fat as adipose tissue due to factors like a high TEF (thermic effect of feeding; increased expenditure to digest polypeptide macromolecules) & some inefficiencies of metabolism (but this is arguably a minor effect, depending on perspective). Excess energy from lipids, carbohydrate, and protein is always stored as body fat (this is elementary). What's less elementary, is understanding the pathways that confer I. preferential use of the energy contained within the chemical bonds from particular macronutrients to perform work (i.e., energy is more readily consumed), & II. the relative efficiency of storage vs. utilization of macronutrients. Depending on the energy state of the cell (positive energy balance versus negative; but under hormonal regulation [see, drugz]) that directs the coordination of anabolic (energy consuming; building of tissues) versus catabolic (energy producing; breakdown of tissues) processes.
With respect to I., whereas carbohydrate is efficiently broken down to glucose as a substrate to perform glycolytic efforts as muscular work (rapid energy); protein must be catabolized (proteolysis), its gluconeogenic amino acids (not all AAs are gluconeogenic, some are ketogenic that can never become glucose) are used by the liver in gluconeogenesis to produce glucose that can be used for glycolytic efforts (e.g., bodybuilding-style training).
Dietary fat is particularly hampering (non-conducive) to muscular work in bodybuilding-style resistance training (medium-chain triglycerides excepting): after eating, hydrophobic/lipophilic fats must be digested in the stomach by bile acids released by the gallbladder, are packaged as chylomicrons that enter the lymphatic system in a roundabout (non-portal circulatory) route to the liver. These chylomicrons do not peak until ~3 hr after eating. Eventually, these packages are opened and their fatty acids liberated by LSL (lipoprotein lipase) in muscle or liver. Fatty acids can never be made into glucose but are a high source of energy. Fatty acids can however be oxidized (β-oxidation) & enter the Kreb's cycle as acetyl CoA (in the presence of glucose) to support long duration, low intensity exercise (e.g., low intensity steady state, zone 2, cardio, etc.) If glucose is low (< 50 g carbohydrate intake daily), ketones are formed & can be used as energy substrates to perform work and by the brain (rather than glucose; the preferred brain fuel).
This illustrates how carbohydrate is particularly conducive to a bodybuilder as an energy substrate (consuming glucose & reducing energy surplus) to perform intensive muscular work, particularly of a bodybuilding-style nature (very high intensity, short duration exercise with long intervals, such as 1RM efforts or power cleans rely more on the phosphocreatine system; here, creatine monohydrate can be used to replete energy stores > any macronutrient).
With respect to II., depending, yet again, on the energy state of the cell (positive energy balance versus negative; but under hormonal regulation [see, drugz]), fatty acids from dietary fat/lipid can be stored in fat cells or taken up into the bloodstream as circulating free fatty acids (that can contribute to insulin resistance if not taken up by the liver or muscles for subsequent use).
Excess carbohydrate is stored as liver and muscle glycogen by the process of glycogenesis. Muscle glycogen stores cannot contribute to blood glucose stores (because muscle lacks glucose-6-phosphatase), so carbohydrate restriction and voluminous total-body resistance training efforts ("depletion training") is an effective means to increase CPT (carnitine palmotransferase) activity, enhancing fat loss & protein sparing.
Dietary protein, in particular that which contains the essential amino acids (that the body cannot synthesize itself) is vital for growth and metabolism. It's not wrong to view it as essential for substantial muscle growth. And yet, it can still contribute to adipose tissue (body fat) stores in an energy surplus. Some amino acids have the nitrogen stripped away (deamination), are incorporated into urea and excreted via urine (it is the peptide bonds that contain considerable energy, and this loss through urea reflects some additional inefficiencies for protein); the remaining amino acids enter the Kreb's cycle. Amino acids that enter the Kreb's cycle are termed gluconeogenic (can synthesize glucose). Amino acids that are deaminated and become acetyl CoA are termed ketogenic (cannot synthesize glucose).
An additional consideration against very high protein diets is that these diets do tend to increase direct glomerular filtration rate (GFR), the rate at which filtrate of the flow from the glomerulus to Bowman's capsule accrues (125 mL/min). They are, therefore, stressful to the kidneys, which might result in medical complications in susceptible individuals, dehydration, etc.