Earlier quoted context omitted.
I am not sure why you are accusing someone of a crime ("stealing"). Installing an ad blocker is within someone's full legal right. Why are you making false statements regarding what is or is not a crime?
It is and it's also within your rights not to use the service, or pay for it. Why should you be allowed to use a service in a way they don't intend you to use it?
The Free Software movement has been fighting against this exact mentality for decades. Digital autonomy should be a basic human right. Anyone should be able to download and execute whatever code they want on their own computer.
Spotify also has this right, of course, and is free to block users if they choose. I am not morally obliged to support their business model. At the same time, I choose to have a paid Spotify account because it's more convenient.