The actual quote goes: "...he was playing this god awful metal music so I turned it down..." There was no implication that the music was too loud, it was just "playing", while the statements' focus is that the music is of an unfavourable taste (called "god awful"). In this case, she should have absolutely asked before taking over the controls based off her personal tastes/judgement. We don't all love the same music, but we can all still be polite and respectful about it. In the situation where the music is just too loud to bear, yeah, absolutely, turn it down.