An unpopular opinion can have more or less thought put into it and be genuinely interesting and get up- or downvoted accordingly. Just like a photograph in a photography sub can have more or less thought put into it and an interesting or boring subject and get up- or downvoted accordingly.
Genuine photograph and the people downvote it... In a community named "photography".
Sounds like utter nonsense doesn't it
If it's a well-known artist, looking them up on Wikipedia is a good way to get an idea what genre they make. A website that does this for all songs individually would probably be AI-powered and wrong most of the time.