Nobody likes it when someone blares their music publicly for everybody to listen to. Even if you have your noise-canceling headphones, it's annoying and attention-seeking behavior that gets on most people's nerves. I believe some people do it for attention, but the vast majority do it because they don't care about how other people perceive them. They're just in their little world and don't care if their choices annoy people for however long.
Parents especially are guilty of allowing this to happen with their children's iPads. Many parents tend to tune the noise out in their homes because it's constant, and if they listen to Bluey intently for hours, they'll go insane. But when they're in public, I believe parents should be smart enough to turn off the sound of their kid's games or not allow them to watch loud television in public places. One mom tried to let her kids blast their iPads on a crowded plane, and a thoughtful mom and flight attendant were not about to let that happen.
