The throttle (on a gasoline engine) controls a valve, usually a butterfly value or a slide valve, and controls ONLY the volume flow rate of air. In a carb it is the pressure drop across the venturi (which is affected by throttle position) that mainly controls the fuelling (on a simplified carb, obviously it's rather more complex than that), and an an injected engine it is either an electronic or mechanical system that decides how much fuel to inject based on throttle, load, rpms etc etc etc.
To say the throttle controls the fuel directly (as I understood you to have implied) is wrong.
Of course, wthout combustion there shouldn't be combustion sounds, but that is the limit of the LFS engine. But a real life engine will develop noises due to work on the air itself, and the volume/tone of that noise will be controlled by the throttle valve.
Take an engine. Remove fuel system. Spin engine (either via transmission and road friction or by alternative means) up to a decent speed, and it will make airy noises. Hell, get a tube with a piston in it, and move the piston - the tube will make a noise.
I never said LFS was perfect, just that it wasn't far wrong.