It is difficult to understand why they use those words when that is clearly not the information provided, and when some tracks don't even have lyrics. It is misleading, and potentially confusing.

Spotify has a contact page for feedback.

I wonder if you might get a better response if you present this as something which is confusing for their customers trying to search for songs, rather than as a grievance on behalf of songwriters (whom I suspect they may not much care about)