Said it in another thread but while sure it matters, it’s generally a pretty weak argument. It’s your ears and you can decide for yourself but even if it does not sound loud, over the course of a ride it can still be high enough to slowly cause damage.
To me it’s the same kind of argument of friends who would say it’s ok to shoot shotguns without ear pro. Sure it can be done but it adds up.
And I don’t mean this the wrong way. Your experience is anecdotal. Maybe you ride in a city and slow speeds, maybe you have a windscreen that actually does decent job of creating a bubble over you, maybe you don’t ride for extended periods of time. Too many variables to account for. For the population though, ear pro is recommended for Motorsports. I had a bike once that caused buffeting from the hand guards. It might work for you but generally does not work for many.