No. The person responded by trying to diffuse things:
he was like “sorry sorry sorry. Okay” and he put his hands up.
That doesn't convey any sense of guilt, it conveys that he was trying to avoid a fight. he put his hands up. That's how you show someone, "look, I'm not a threat, I'm not going to hurt you. you win." It's a strategic decision, not an admission of culpability.
He backed down and surrendered in the situation because it wasn't worth getting into a confrontation about it. Unlike the commenter, he was able to keep this interaction in perspective.
And it's this part that makes me think wanderer was probably threatening and rude. If wanderer made a normal, calm, polite comment/request, this is an unlikely reaction. It is likely occurring because the person on the phone thought they were in some danger.
By "Stay on their phone" you mean keep doing as they were (ignoring your request) right?
I don't know why everyone here is so grumpy about other people enjoying their phones but if you are grumpy about it, I think politely asking someone to turn the volume down or whatever is the best way to deal with it. If it's really so unpopular they'll be getting always asked to turn their phones down and eventually get earbuds or subtitles or whatever.
I'd be interested if you phrased it as a question somehow, maybe it might be more fruitful. Less dramatic/tense for you. Like maybe "excuse me I was just wondering if there is a reason you are playing that so loud? It's bothering me." Would need to workshop the phrasing to be less dickish than that. But maybe you'd get some kind of interaction you'd learn about other perspectives. There must be a reason right? Like idk I only ever play things out loud by mistake when Bluetooth or the AUX fails and I find it humiliating for anyone to know what dumb podcasts I have on. Sometimes I take the earbuds out and hold them away from my head to make sure nobody can hear even by accident the stupid shit I am listening to. I would love to know more about how people are just doing everything with no worries in public. Maybe they have a useful philosophical contribution I hadn't thought of. Or maybe they can explain to you why you shouldn't be bothered.
How about this: "Hi, I was just wondering how you find it when other people are playing things really loud on their phones?"
Honestly, it's a bit passive aggressive but that would probably be more likely to make them turn it off immediately as they might not want to engage in a conversation like that. However every so often someone might take you up on the conversation and you could share a few minutes together as humans.