Why are motorcycles so loud?

Unfortunately, traffic citations aren’t. While I love the sound of my bike with no silencer, I already have enough attention on me from the fuzz just for riding a sportbike. I haven’t been pulled over on it in about five years and have never received a ticket riding it, so I must be doing something right. I seem to have better luck on it than in my car oddly enough.

Well one of the places where motorcycle noise is the least obvious is inside a moving car.
Even if the driver has their window down, and stereo off, what they’ll hear is the sound of their own car’s engine and road noise, the wind blasting in, and the sound of other vehicles, which is difficult to separate out into separate vehicles in discrete locations.
And we’re not talking about a short, sharp noise like a car horn. We’re talking about a sound that could be part of a part of a driver’s ambient noise for some minutes.

Of course I am not excusing the driver who pulled out; (s)he should have checked his/her mirrors prior to doing the maneuver, and indicated in good time. I’m just expressing skepticism as to how useful a loud engine could actually be.