In my experience 99% of people will turn down the volume or use headphones if you ask nicely.

I never in my life was confronted or even assaulted, even by noisy teenagers or grim looking men.

Not saying it’s impossible but I would guess it’s very unlikely. Ymmv

He's not completely wrong though. I was assaulted (pushed and fell to the ground) for asking someone to turn down their music at a pool. And I think I've asked less than 20 people in my life to turn down their music.

It 100% depends where you're at and the culture of that place, along with your perceived threat level.

People that are perceived as no threat or a 100% chance of being a deadly threat if ignored typically have no problems here. It's the grey zone where conflict shows up. Think of a little 60 year old grandma asking nicely the vast majority of people will listen. Same if you're a 6'7" slab of rock with tear drops tattooed on your face. Meanwhile if you're a minority asking a racist to turn down the volume, this situation is going to cause conflict almost all of the time.

99% is way too high. More like 30 or 40%.