It’s just an excuse, if they wanted to be noticed there are much better ways to accomplish it like headlight flashers during daytime. Not to mention some are so loud they create a distraction for other drivers and drown out all other noises which is inherently unsafe. If I can’t hear my car horn (or myself think) over your Harley how the fuck am I supposed to drive? That’s no different than wearing headphones while driving which is illegal for the exact same reason.

Plus, think about where the sound is exiting from compared to where most motorcycles are hit (someone turns left in front of them.) You don’t even have the person most likely to kill you in the direction of your sound waves. It’s just a talking point.