When people post a link to a song, there is no way to tell what kind of music it is or what period it’s from. To help engagement and the user experience, I suggest we require people to at least write the genre and year in the title of their post. Bonus points for adding some explanation in the body of the post about the significance of the song and why they’re sharing it.
I think people have the right to choose if they want to listen to something within their comfort zone or not. People have a generally good idea of what they like and don’t like, and it’s very reasonable for people to want to discover new music within genres they are familiar with.
You’re making some assumptions about how people operate that I’m not sure I agree with. But maybe you can make a different community - genre-specific or something. Or just live dangerously and click the genre-less links.