I mean obviously you would want more protein than fat because otherwise youd just be building equal amounts or something but I mean can't you burn off the fat later once you get enough muscle.
That's what most bodybuilders do yes. The idea is to pack on as much muscle as possible while gaining the least amount of fat. If you simply don't care about gaining fat, then you could not watch your diet as much and gain both muscle and fat. That's only if you don't care though. Lots of people do. Including me. I hope this answers your question. I may have misunderstood your question though. It wasn't very clear.