Imagine a grocery store has a promotion - you can get a loaf of bread for free if you listen to a twenty minute advertising presentation. Does this justify not going to the presentation, and just stealing the bread?
Bear in mind, this loaf can also only be eaten inside of the grocery store. You cannot leave the store with the bread, because it is welded to the infrastructure of the grocery.
Not paying for a gym membership would be a better example. You're using up available capacity without giving the gym a way to monetize your presence there.
If you don't like that they have an ad based model, and personally want to boycott their subscription service because of it then do so and buy your own music.
It's not complicated. 'Not rewarding their behavior' is simple - don't use Spotify. Anything else is very transparent, after-the-fact justification of your desire for theft.
"Hey I really like this bike share service, but I don't think it's safe, so I'm gonna steal the bike, improve the safety and then ride it whenever I want. I don't want to reward their behavior of renting bikes I feel aren't safe."
