> knowing about my music taste

As with almost all arguments against exercising privacy, this is merely a failure of imagination on your part. Spotify doesn't give a shit about your taste.

Next time you listen to music, think about all the possible data that could be observed simply from you pressing play. What time of day is it? What day of the week? Which device are you using? Where is that device? Is this an unusual genre for you at 8pm? And so on. "You listen to indie rock" is harmless data. "We know the all your emotional states from the past 10 years and also those of your whole family" is at least a little scarier, right?

Combining large amounts of data about how you use a single app can tell a lot about your life. You may say this is overblown, but if you do want to hold a true belief instead of a convenient one, start by acknowledging the enormous amounts of data Spotify actually has about who you are and how you live.