Got it. You don't actually have any proof that riding with earphones is always illegal everywhere, every time in the US, but you're going to lie that it's always illegal, everywhere, and every time in the US until proven otherwise for the sake of an online argument.
I have three PDFs of DC bike laws, and none of them contain the words "headphones", "earphones", or even "music". So, yeah, even here, where a cyclist mayor is trying to push cycling further into the mainstream (as if it even needs his help anyway), using a music player while riding isn't (yet) an issue.