I haven't heard that one, but there's a similar one in the Frank Zappa Book about the song "Montana". He wrote a song about dental floss, yet people's teeth didn't get cleaner.
A song can't possess someone and make them do something, but it's a juvenile and ridiculous argument to claim that the media we take in doesn't effect us in some way. After all, we use it because we like its effect; maybe it's relaxing, like jazz, or exciting, like a fast-paced video game. But either way humans are learning beings, and everything we see and hear is filed away and used as reference later. It is almost impossible to turn this off.
Speech shouldn't be censored but individuals should choose wisely what they decide to surround themselves with. Thought is father to the deed and the media is actually about implanting ideas and emotions in people -- we should choose carefully that which we let through.
But either way humans are learning beings, and everything we see and hear is filed away and used as reference later. It is almost impossible to turn this off.
Although that's true in a general case, you're making a false dichotomy. All in or all out. However the people who want to ban music are not making claims about specific general moods. They are saying "These words cause people to be killers". They are taking your preposition "music affects feelings" and turning it up to 11.
I can't tell what point you are trying to make. Is this a convoluted argument for censorship? Are you claiming that there is a direct link between the content of media and the behavior of people? That's a pretty big claim, if so. If not, then what, exactly, is your point?
Everyone chooses what to surround themselves with. Perhaps it would be better if people didn't choose quite so narrowly to only listen to the voices they agree with, and try to diversify their surroundings/inputs a bit more. If we all paid a bit more attention to the cultures and interests of other people, perhaps we'd be less inclined to distrust and dehumanise others.
I apologise if I'm assuming/misunderstanding things, but I genuinely don't understand what you are trying to argue for here. Watching horror films evidently doesn't make people do horrible things, so any link between the content of media and its effects on people can't be that simplistic.
"There are more love songs than anything else. If songs could make you do something we'd all love one another."
--Frank Zappa