There is no good reason any ratcheting mechanism would be noisy. It would be either from poor engineering, or because someone purposely designed or altered it to make it noisy because they need the attention their mommy did not give them when they were nursing.
The Sun and Shimano and Sachs freewheels on my old ten and twelve-speed bikes are very silent, so the engineering has existed for many decades to make them so. If the ratchet in my hub was as loud as the one in a late-model Specialized I was following Saturday in the TT, I would be inclined to take it apart and see what was wrong with it, or if it was running dry without lube.