I think her lack of amusement was more of a "my mother has never cared for toilet humor and especially didn't care for her teen son laughing uncontrollably in a public space" thing. My recall of an event that happened about thirty years ago may be imperfect but I'm fairly certain the old man in question was fully aware of what he was doing, he just didn't give a shit about the noise he was making. I'm not certain how old you are but I'm finding that as I age, I'm similarly having less shits to give about certain etiquette protocols. That said, yeah: poverty is a serious issue and we should collectively do a better job of supporting each other.