I agree with you that you are never "forced" to pirate; you can simply not listen to the missing album.

But many many many many excellent albums are not available for sale anywhere at any price. They essentially do not exist, except in the hands of a few collectors.

The bands themselves, the creators of said music, want their music to be heard.

The fact that they aren't available for sale or streaming is often because a rich bureaucrat can't be bothered, not for any legal reason.