I have to disagree. Loud pipes (not obnoxiously loud, just loud) do bring awareness of the bikes presence. We ride bikes, so it is in out nature to always be on the look out for someone on a bike. A lot of people have never ridden a bike or know anyone that does ride. So they tend to be less aware of riders.
Personally I don't see any difference between someone that has loud pipes, a loud muscle car, or someone that plays their radio too loud. It is a "cool" factor for the person. I may not want to hear the vehicles, but I don't want to infringe on their civil liberties either.
Who we want to think of us as cool directly effects how we try to be cool. I have have a pair of sponge bob square pants pajamas because my kids this that is cool. I could give a dam what the guy next door thinks of them.
So I think it has more to do with who we want to impress and less to do with penis size.